My receipt doesn't have the part numbers but here is a list of all that was done.
Camshaft,Timing cover gasket set, Head gasket set, New water pump, New oil pump, Lifters (8), timing chain, stretch headbolt set, valve lifter (8), oil cooler seal, cam retainer plate, and main drive belt. I will be towing it back to the shop tomorrow what questions should I ask I should be able to get part numbers too.
Well, you want to know the brand name and part numbers of the stuff they used to repair the engine. Replacing the VLOM when there is AFM failure is SOP, especially since there's a more reliable update, same for the valve cover. Now if they did not replace the VLOM, what are the chances that they did not replace the filter under the oil pressure sensor? That part being clean is critical and just $6. They could have cleaned it in the parts washer and put it back too though.
Since they also replaced the oil pump, make sure they used the right one, telling you it's a "high volume" is not sufficient. You have an all aluminum engine, the pump is supposed to be the 12612289 aka the Melling M365.
The main reason the lifters collapse is because of VLOM failure. It doesn't have to completely stop working, just get clogged up and or slow down the activation of the solenoids and they'll quickly take out the lifters.
I would insist on GM parts, especially those De-Ac lifters. Verify that the camshaft used is an AFM/VVT camshaft and not some Chicom garbage or a Melling replacement for a non AFM motor.
Consider using this opportunity to delete AFM physically from the engine, you can use the camshaft from the L9H.