Not really, I'm mostly cribbing from Wikipedia and here:
The hand-guard is the most obvious thing, and is A1. I did hesitate to even point it out, but it's genuinely a poor show by PatrolBase (or anyone else) to claim that it's an A1 receiver, which it clearly isn't.
Hmm, are there any actual A1s?
The CYMA "A1" receiver is closer, but still has an A2 stock, grip, birdcage and slip ring. https://www.patrolbase.co.uk/cyma-cm-009a1-m16a1-assault-rifle
G&P looks pretty good, but at a much higher cost: https://gpairsoft-uk.com/shop/en/50019-gp-airsoft-m16a1-aeg-gp-gp290.html
They even do a recoil version of the very early pattern with no forward assist: https://www.gunmart.net/gun-reviews/airsoft-guns/bb-guns/gp-m16a1-recoil
The thing is, the BBs won't care, and neither will anyone else except stitch-counters.