Thank you for responding
@swathdiver,
What I meant by "high end struts" is that they were OE, not cheaper makes. Not sure about the pre-assembled question. Ordered from RockAuto.
I just called three GM dealers to confirm the part #'s by VIN:
The suspension is:
Zw7 GM part #: 20955486
I installed ACDelco: Front -540615 Bilstein: Rear -24186933
The parts guy said the ACDelco part I installed is the exact same OEM part he has.
I'm amazed that I have what they are calling: "Suspension Package, Premium Smooth Ride".
It's not "smooth" over any kind of bump.