Snopro,
The pic below shows how the bedside aligns with the wheel when the rear is aligned with the rear cross sill. The middle stake pocket is just off of the centerline of the wheel. The S10 bed has 43.5" between the wheel centerline and the rear cross sill, while the '54 bedside has 43".
Hopefully this does not put the wheel too far in the front of the fender. If so, my worst case would be to cut and lengthen the bedsides behind the rear fender, and shift everything from that point toward the front. Not a huge deal since I'll have the material from when I shorten the front of the bedsides, but still something I'd rather not have to do-there are plenty of other projects that are consuming my time.