Welcome!
I've toured the Bowling Green Kentucky Assembly plant a few years ago, went there in a car that was built there and got to drive my Trailblazer past old Moraine Assembly a few times and just thought it was awesome. When I grew up, my dad worked in a plant that stamped blanks for many models of GM vehicles, many for the GMT800 line. Some times I wish had had got into production management or project management instead of healthcare but so is the way of things.
Back when it was still GMI, a cousin of mine was the youngest GM certified master tech to graduate from there.
I can't help to notice that you seem to be a I6 guy, and with you being a GM guy I probably have way too many questions about the late (06+) LL8.