I sent my cousin an email asking about LS1s and high copper in the UOAs, I figured he would know since he's the engine test engineer at the LS1/LS6 assembly plant! I don't know why I didn't think to ask him this before! Anyhow, here is his response:
Cam bearings have copper in them. You can see copper at the joint in the bearing. The copper levels you're referring to are not serious. It is not like the bearings are wearing out. If that were the case, the copper levels would increase over time. What you are seeing is probably just the residual copper at the bearing joint.