Demon and Dart Sport Scoop Location
Well, I must say I tend to agree with Old Demon. Unfortunately, I have yet to locate a verified, original 72 or 73 a-body with these fresh air holes used with the snorkel scoop. I'm not questioning your sources or background information, but having a vehicle like this myself (and having purchased it at the time these vehicles were only 3-4 years and still plentiful in original form on the street), I've found no evidence to support the notion of these fresh air holes installed at the time of vehicle manufacture. Over the years, I've done a considerable amount of research, too.
The factory hood used on all these vehicles shows cutouts in the bracing for the holes in the dual scoop locations -- but there are no similar cutouts in the bracing in the snorkel scoop location. I think that is very telling.
As for using the snorkel scoop without fresh air holes, I can testify that it's no problem at all. As I said, my scoop was added by the dealer in 1976 without adding the holes, and it held up fine with no damage for nearly 30 years. I only added the fresh air holes two years ago at the time I repainted the vehicle (the holes look good, plus there may be minimal performance advantages to having a flow of fresh air into the engine bay -- that's why I decided to add them).
I'd love for somebody to produce factory documentation (i.e., vehicle order form, broadcast sheet decoding, etc.) proving this performance feature in 72 and 73, but unfortunately, nothing has turned up.
Oh well...