Great truck!!!
Depending on your plans, you might also consider the 9.5" 14-bolt in a 6-lug configuration from a mid-90's 1500 "heavy half" or 2500 pickup...find a 2500 with a 6-lug pattern. That way you can keep the pretty rims.
Check the glovebox RPO list for GT5 and it will have 4:10 gears. GT4 means 3.73. G80 means it has the gov-lock...which I really liked in my daily-driver burb that also saw some dirt action. If you wanna slip in a lockrite, you'll wanna make sure the G80 is not listed.
Or...you can swap in a 10.5" 14-bolt, like the one in my avatar.