I bought a used BCM upper and the bolt carrier doesn't have the white BCM lettering that I see on other BCM bolts. Does anyone know if they make/made them without the white lettering? Also, is there any other way to tell if it is actually a BCM BCG? I'm hoping the seller didn't pull a fast one on me and keep the BCM BCG and give me something cheaper. The gas key is properly staked. Thanks for your help.