Bought used LS6 - need help please.
Upon removal of the included heads prior to installing my TSP LS6 Stg 1s, the shop noticed there were two different sets of pistons. On one bank there were what they assumed the factory stamped pistons, and on the other side there were pistons that weren't stamped. Now he did say there was an even amount of carbon buildup on both sides, so he guesses it was ran that way. Is this something to be concerned with. Seems like a lot of money to spend to have things go wrong due to this.
Does anybody have any idea why there'd be different sets? Did GM install these unstamped pistons when they were doing the piston slap recalls and rebuilds? This is out of an '01 Z06 w/ 18k miles if that matters. I know new pistons could be pressed in, but I can't afford that as of right now.

Like I said, 4 of mine have this marking and the other 4 don't.






