The Sweptline short box bodies fit well on the 73-93 short box frames, I've done that.
Fitting a standard cab onto an expended cab frame has its own set of challenges, now add the complex nature of at least 3 major frame changes between the cab and the chassis, and it could be fairly easy, or really hard!
The wheel base being the same would help, but also needing consideration is the relationship between where the body sits on the frame, how the front wheel wells match up, and how the motor sits in relation to the firewall. Most of the older trucks have a short nose, the firewall sits closer to the front of the truck, then most of the newer stuff.
I suggest you park the two trucks side by side and compare. It may be so close it looks like they intended it to be, or it may be so far off it will be really hard to do. Gene