No, the law doesn't really make sense.
The first of the Colt AR-15's are now becoming of age for C&R status.
While there may have been some minor changes, functionally they're identical to the current platform.
To me, it would make more sense that a "C&R" FFL should allow the holder to purchase any firearm (other than SOT types) directly without an 01 intermediary. After all, you've already been through the background check so what's the purpose other than an additional fee? As long as the 03 FFL holder is not engaged in the business of buying/selling/repairing firearms and they're for personal use/collection seems it would make much more sense...
Mosin-Nagant Custom Shop/Bent Bolts
Gun-Kote/ Cerakote Refinishing
Criterion Barrels/ Savage Re-Barreling