86 k10 rears?

[SquareChevy]

(((STORY OF WHAT HAPPEN)))So I was driving me k10 home from work when I started to get this loud humming noise from the rear and during right turns it would knock, instantly I thought I broke teeth off the gears or something. Turns out the rear was empty of oil and the carrier bearing was completely shredded and melted looking...
As I went to the glove box it showed I had a g80 locking rear! (never knew that till recently, was very surprised). Of course my k10 is the odd ball with the 12 bolt rear.
(((REAL PROBLEM IS HERE)))For the love of me I CAN NOT find another 12 bolt 30 spline g80 rear within the years 74-87. I went to many junkyards and all I can find is 10 bolt rears with g80's. I don't feel like buying a brand new posi system, I'v been doing some research and it says 74-87 blazers/trucks have g80's.
Now since I cannot find any 12 bolt rears with it in between those years, I'm wondering what chevy/gmc used above 87? Did they continue with the g80? And if they did what changed past 87? And could I still use the g80 thats above the year 87 in my 12 bolt rear as long as the g80 I find is still 12 bolt? (P.s my gearing ratio is 3.07 or as others say 3.08)Right now I'm running an open diff, only one I could find not fun, hard to do donuts in the fields