Although a quick search found
this 2005 in Northfield MN, fully loaded with 100k miles for $15k.
Here's
green 2002 in St Charles MO.
FWIW, the 8th character in the VIN is a "G" if it has the 8.1L. GM also uses a sticker in the glovebox that lists all the options on the truck, option GT4 is the 3.73 axle, GT5 is the 4.10, and G80 is the posi option.
Most of the time the the folks selling the truck have no idea what the axle ratio is in it. Here's what the glovebox sticker looks like, look for the GT5:

Also bear in mind that GM trucks of this era are having issues with brake and fuel lines corroding, GM used uncoated steel to save $.10 per vehicle. You can buy complete pre-bent kits, I changed all my brake and fuel lines over to stainless a few years ago. Pay attention to corrosion on these lines if buying from a snow state.
Regarding suspension, all 8.1 Suburbans came with the AutoRide Option, which on the 2500's is NOT air leveling, it's real time shock damping using ferrous fluid. The system uses a separate ride control computer, a ride height sensor at every corner and very expensive shock absorbers $250 EACH). It's cool in the sense that it will automatically stiffen the shocks when in tow/haul mode, etc. That said, I bypassed the system and installed KYB Monomax shocks at 125k miles since I didn't have the coin to spend a large on just shocks. Still rides great IMO.
You know all the quirks about the X since you own one, I figured I would give some info on the burb if you are looking at buying one.