Need help to ID Bushmaster upper and compensator

[ToyotaMan]

Does Bushmaster stamp the model of an upper somewhere on the barrel or upper receiver? I have what I think is a 20in" PostBan National Match A2 upper that I want to sell, but I want to make sure that it is exactly what I think it is so that I'm not advertising it incorrectly. I'm guessing that is what it is from looking at Bushmaster's website and comparing the pictures to the upper.

I don't have the specifics because I bought the rifle that this upper came off of from a private seller and I didn't get any paperwork with it.

Also, it has a compensator on the front end. How do I know if it is "pinned" or "welded" or affixed in some other way? It has 9 holes on the top in a 3 by 3 pattern, and then three larger holes on both the left and the right. Maybe someone who is familiar enough with the compensators available might be able to tell the manufacturer from that description.

[RMTactical]

Bushmaster barrels should read B MP (insert twist rate here).

Any pics?

[AtreidesAR15]

Hey Toy,

I can't help you with the make of that compensator, sorry. Alot of Comps have 3 ports on each side, but the 9 holes on top has me stummped. Anyway...To check if your Comp is welded, simply check for a dimple or dip in the comps surface at 12:00 o'clock and 6:00 o'clock. There won't be any such defects in a screw on compensator.

[centennial]

Bushmaster does not put compensators on their National Match uppers, so if this has one it was pieced together by someone other than the Bushmaster Factory