I don't know if this info is any good, but here is my deduction.It seems quite a few of the guys on this site have used the long box/reg cab 2 wl drive in their AD trucks with good success. Now if they use the same box in the 54 and 55 1st series as the newer ones ,right on up into the 80's, it seems to me you should be able to use the S10 frame in a 58 Chev/GMC.
Lothar.