so as I'm looking to do a black hawk down delta load out I need a ar-15 and I want the bolt lock and that means GBB or EBB and as its hard to find WE m4s at the moment im looking at the EBB but as all the TM ones are m4a1 style I'm looking to see if any knows if the TM m4 will take a G&P or outer company a2 upper receiver.