Both Bushmaster and DPMS are still selling A1 (actually C7 copy) uppers, with forward assist AND the shell deflectors. Any others you may see listed in this or that web site are actually DPMS pieces, and I don't care if they call it by their own brand name.
The DPMS piece is less expensive than the Bushmaster, but the color is almost certainly going to be a bit more "off" than the Bushie. Neither is going to be an exact match, but the Teflon coating that DPMS uses on it's pieces does change the color just a bit, so that you rarely if ever get a close match between a DPMS unit and another brand.
Understand something. You're likely to get at least slight differences in color and "tone" of upper/lower combos, even in the same brand. Slight differences in shade are a fact of AR life. Pieces made on different days in the same plant may dry diiferentl;y, or be sprayed with a different lot number, or ????
You might conceivably find a dealer at a show who is selling new A1 type uppers, but I'd call that a long shot. At least a long shot here in Georgia.
Colt and other milsurp pieces in abundance down here, but the only commercial A1 type I've ever seen was a DPMS. slightly used C7 job----and I bought it for the C7 clone I was building