Actually I think they were marking them before that since I want to say my first BCM upper and BCG were bought in 2011, but even I ain't sure. But again, I was giving possible options. That said, I don't know shit about the screws, I generally have other details I am more concerned about, of course I by my BCM BCG groups from BCM, with the lone exception being from Rainier, so the screws I defer to someone who knows that shit. Edited prior post for that.

