I put all my 90 stuff into a 88 cab. PAIN IN THE BUTT as almost nothing is the same between them. About the only real things that stay the same, windshield, rear window, door locations and the opening in the firewall for the heater core. EVERYTHING else is different.
On the other hand, I cut the headlight buckets between the two, and used the 90 buckets for the 88 cab. Not the best solution, but cheap...