WDZ,
I know what you mean about blowing up the pics - some of them are really tough to see. I have a magnification setup that I use sometimes when I try to figure out markings/sponsor stickers on blurry 40 year old B&W photos.
Anyway - CSX2287 was the first car built. It was also the only body made in the US. The rest of the bodies were made in Italy by Carrozzeria Gransport. Sometimes Italian craftsman do things their own way - and they did this with the remaining Daytonas. Some things got 'fixed' in Italy. It made the cars a bit slower than Brocks original design (IIRC), but they looked a bit better.
All of the cars made there (CSX2299, 2286, 2601, 2602, and 2300) had the wider space between the hood and door. They also had scoops on the hood and cowl, while 2287 only had them on the hood.
Those holes were for airjacks, and some cars had them on the right, and some on the left. Sometimes a plate would get pop-riveted over the holes for certain races.
The construction pics you saw may have been either from Italy or CA. The Daytona book has a bunch of pics showing construction at both places.
There were a couple of other Daytonas built (Willment and AC), but they are completely different animals and can not really be mistaken for any of the other 6.