When I bought my '85 Burb,I was elated to find an identical one that had the same color scheme and barn doors at a local pick & pull....
I wanted one with the barn doors but mine had a tailgate (badly rusted one too!)...so I bought the 2 doors and the hardware for 50 each,with the agreement I could get a refund if they would not work..
Well,I ended up taking them back after reading a few posts here about converting from a tailgate to barn doors--the guy at the boneyard aid he was pretty sure that after 1978 you couldn't just swap from one type to the other any more,it used to be a bolt on swap back then,and posts I read here confirmed that...without changing the bottom sill and adding reinforcement and plates to bolts the hinges too,its no do-able...not by a backyard hack like me anyway...I'm not very good at body work..
I was bummed,because I dont much care for tailgates with electric windows...I did score a fairly decent tailgate for 40 bucks though,but its been stored away,no sense in letting it rot on the truck while its sitting in my driveway for 3 years now..

...mine is a 6.2 also...not sure if I'm going to keep it now...the thoughts of paying 165 bucks just to fill its 40 gallon tank isn't exactly encouraging,never mind the other things it needs fixed to be roadworthy now...
If I had any cash I'd put it on the road before its junk from sitting too long,ditch the ailing 700R4 and swap a 4 speed or th400 into it,and use it...it sucks,I bought the truck real cheap and did quite a bit too it,added a fisher plow setup to it,but ran out of money and ambition to do anything with it...had minimal rust and a mint undercarriage when I got it too...