I can not speak for Joel or Marty but they have said in the past, that some old paperwork was found on some of the old cars.
There were, of course, far more potential Motion cars where nothing was found.
They never said there was a list of vins or a lot of info found but one interesting story is in the Motion book Marty wrote that Joel found the 1970 yellow Phase III GT after a 5 year search that started in 1985 , it changed hands a few times, was painted black, found in Minnesota, but had the correct VIN . This is on page 138 and 139 of the Motion book.
In a SuperChevy article on same car, Marty writes "Rosen was able to supply the car's original paperwork including customer invoice and shop orders, insuring the restoration would be totally accurate"
I don't know what exactly was found on the old cars but I don't find it hard to believe that at least some info was found.
Here are a few reasons why ,
Joel had the same home and same shop in LI NY from the mid 1960s into the 1990s,
Marty worked in the automotive publishing business from the mid 1960's to present,
when you talk to them in person, they can recall many small details and stories ,
I have seen for myself that they both saved items from back in the day,
I know some documentation was found by collectors because Joel supplied original owners names on some cars,
Joel helped collectors like Otis Chandler find top level documented cars in the 1980s,
Joel bought back some cars, and other reasons.
SuperChevy article on the yellow 1970 Phase III GT
http://www.superchevy.com/features/v...ion-corvettes/
article on Marty's blog "Car Guy Chronicles" with some info on Otis's cars and finding other cars and original pictures
http://www.carguychronicles.com/2011...tion.html#more