Having found another ad, I think it's probably a 2007 (or at least I found a listing for a rolled 07 Express, googled the phone number and get the same address as the other ad). Wrecked pretty well:
It could be a different vehicle but it seems pretty likely that it's the same one.
Would a 2007 van be drive by wire? Gen3 or Gen4 engine?
I wonder if I could get the tank to fit somewhere. I thought it was 1987 Blazer (or later Suburban) that people liked to use. Sadly my utility bed is welded on, so it'll be a total PITA to put a tank behind the axle.