First things first....I have been lurking for quite some time and I have to say, this is an incredibly useful forum, I have learned so much here. I am working on my first 80% lower and plan on putting together an M4A3 forgery. up untill recently, I had planned on a kit from either model 1 or M&A but I plan on using a Knights RAS II or a ARMS S.I.R. I have been told these will only fit a mil-spec upper. Does anyone know if the model 1 or the M&A Parts uppers in thier kits mil-spec? If not, who puts together a kit on a mil-spec upper?
Thanks in advanced.

They both are.