Yea, thats what I figured, partly why I haven't done it yet. I've got a second lower that I'm trying to build if/when I can get the parts from a dealer and not pay ridiculous prices. Keep seeing some bolts on arfcom selling for around $50 at times and have wondered about picking one up and then swapping the carriers.
Guess I'll just wait for BCM to restock and try to catch one.