To be fair many are not going for 100% accurate restorations either.
Some will take liberty with parts from various years to get the look they like. Then there is resterods and customs. Along with clones.
It is only those going for the 100% perfect factory cars that need to match the standard.
Yeah, I am a great believer in do whatever you want to/with your car.
But don't misrepresent when selling it down the line. More of an issue with the clones, though the recent years increase in hype on survivors does mean knowing actually original vs. faked might matter too.
How much it matters probably depends on how much you are paying for that originality too.
The auction TV world confuses some that # matching engine is a thing for everything. It's not. Most older collector cars you have a date range on the engine and no real proof it is the factory installed engine. Even if it is... for most cars that is just a fun fact and not a big value changer.
Totally different for the high end musclecars where there is paperwork proving provenance.
Although I'd never get so involved in these levels of "restoration", I do enjoy reading articles about the arcane details that can mean "is it real, or is it Memorex"... And even more fun to me is the thought that some restorers and collectors can keep reams of this type of information in their heads.
Personally though, I don't really care about most of this crap. As I remember it, most people I knew who were buying new muscle cars in that era were changing stuff on them almost immediately. Nobody I knew who showed up on the streets on a Friday night in a new Road Runner or Chevelle was worrying about decals on the air cleaners. In fact, most factory air cleaners we replaced with aftermarket stuff on the way home from the dealership. We were Restomodders before the term was even invented!
It's fun to read about, but for the 99% of us who just want nice looking, fun-to-drive cars, it's pretty irrelevant in the big scheme. Just like we did in the day, I'm more into "do what you want to make the car more fun, more drivable, more 'you'".
You give an interesting point of view... insight into a world I am not part of (not sure how to say it).
-On one hand I am fascinated by the minutia but have no aspirations to live that life.
-I find it bizarre that rarity of the vehicle would matter at all. If the best 67 Camaro in the world is the most common spec on record so what? Counting rarity actually discourages people from taking a really great car to concours level because if it is not going to be judged on its merits as a quality example (rather than some imposed pedigree of rarity) take a pass and only do the rarest things.*
Besides... some things that were common are rare survivors. Personally, seeing 5 red 57 Bel Air convertibles done up to superb quality isn't that interesting after the first one.
*I get that a 1 of 1 handbuilt body full classic era car restoration to concours level there is some logic in "that is harder to pull off" than a Model T in theory, but the post I am responding to is talking about regular factory production tri-five Chevs.
Rarity is given only a slight small bonus, more as a tie-breaker than anything else. In a restoration, doing a rarer car properly is somewhat more difficult than doing a more common variant of the same car. (If for no other good reason than finding and fitting the correct parts for the rarer car is more difficult, more expensive and takes more work to do it properly.) But the bonus isn't much, and as was our case, it was the more common but better-done car that took the BiC trophy. Not that the FI convertible wouldn't also have been deserving of it. Had the hardtop been anything less than perfectly done, the win would have gone to the convertible. But that's the whole point of concours judging in the first place. At non-concours shows, I suspect the convertible would have won every time. In your example of 5 red 57 Bel Air convertibles all lined up, the challenge of differentiation would have to come down to minutiae in order to make the final BiC determination. For a spectator, they may all appear the same. To someone with the responsibility of judging, it's a different sort of challenge entirely.
Everything I have done to my 69 Mustang has been in the spirit of "Day 2".
Fun for me, and way better looking than the "day 3 rotting in a driveway not moving or able to" look I bought it with.
I won't complain about what it sells for though, proper restoration is the timeless safe thing. People that know what they are doing can make money on some things resto-modded. Most people shouldn't even think about vehicles as an investment.
Restoration is either of two camps (maybe three) "make it my way" to get the look/style or "how it should have been ". Total OCD where every nut bolt piece & part needs be just as it was off the factory floor in 19**. The third I mention is more in the "make it my way" camp. The person restoring but may be budget or even safety conscious., borrowing from different years or models to get his project done. I have done this with my '64 T-bird convertible. I like the lines and small differences of the '64 T-bird it is why I sought it out. The brakes are another matter. I just wasn't comfortable with the drum brakes in front for a few reasons. The '65 model year had front disc brakes and if you dug a bit dual piston calipers could be had.
Well, I think most of us don't call the third way "Restoration" - rather, it's known as "Restomodding". And it's what a TON of people have decided to do - for safety, driveability, reliability, efficiency - lots of reasons. We used to do it back in the '60s and '70s - we just didn't know what to call it! 😀