i imagine it was bought right from pri, i picked it up in the marketplace here.
the upper says precision reflex on it though.
If it is a PRI factory upper, you may wish to re-torque anything with threads. I had a factory PRI MOD 0 where pretty much everything except the barrel nut and muzzle break came loose in the first 600 rounds. On a MOD 0 that is a lot of threaded fasteners.