How do you tell if an upper has been manufactured by Bushmaster? I am looking at a preban Bushmaster lower with an A2 upper. The upper has a 16" fluted barrell with birdcage flashhider. The guy says it is all Bushmaster and that this is the original pre-ban configuration but the upper is an entirely different color than the lower (kind of purple). What markings would be on the upper?
Thanks in advance for any help?