I seriously doubt you will find any new... the good news is that because they are totally hidden from sunshine they don't sun rot and get as brittle as most of the rest of the plastic bits. The bad news, with the no humidity you and I share in CO they are still pretty brittle... best luck is a junkyard and better luck at finding even less brittle ones would be junkyard in the rust belt.
Don't know where in CO you are, but Atwood Auto and Metal has a few 2nd gens, Anderson Salvage in Greeley a few 2nd gens, and Martin's supply (I think it is now called Ironmountain salvage) near Windsor/Loveland has at least 2 2nd gen that I remember (I stole the headlight bucket rubber from 1 and the B pillar interior trim from another)... Don't remember if any of those had tailgates or what they looked like - mine is in pretty good shape so was not shopping back there. The one I took the headlight bucket had a perfect front end, no sun rot, no damage, no repairs from a collision, it looked like a garage queen.
All 3 of those are owned by some big corp, before it went big corp, they were all bought by Andersons .... They still opperate kinda ma/pa - no pictures, the entire lot is "row 1", so it is just a hunt for what you need.... if you are closer to the metro then LKQ Pick your Part has a rotating stock all the time and I see 2nd gens come and go in both the Aurora and Denver locations.