Guessing I have some restrictions due to being a new user, but I can't send a PM for some reason. Looking at your profile and being in NJ, shipping will likely be a big cost. I was looking to get $100 for it with local pickup. I can get a shipping estimate if you provide a zip. Attaching pics to confirm we're talking about the same things.
Old post I know, but have one out of a 2021 Chevy 3500 if you're still looking. Not sure if it would fit. I removed it to make more room for my dogs to lay on the floor.
Got a 2021 Duramax LTZ 3500 DRW at the end of December for roughly $66k:
MSRP - $76K
-$7700 Employee discount
-$500 Customer cash
-$1500 Dealer discount
With low inventory everywhere on DRWs I wasn't getting it any lower - trust me I tried!