Well we picked him up today and I confirmed it is an M4 and not an M4A1. Even though he hasn't been allowed to rock and roll with it yet, it has the 3 shot burst mode and not full auto so it is an older one from the original contract, since the a1s have full auto (back to the future anyone?)
I guess now it's just a WAG...does anybody know when did the contract with Colt go from the M4 to the M4A1?
Maybe I can give him a range of "no older than and no newer than..."
And it must not be too bad, he qualified expert with it...