David,
My Chevy '50 COE has no shocks, a wheelbase of 158" and GVW of 16,000 lbs. I usually drive it for fun empty (weight about 7500 lbs) and the springs are very stiff. The heaviest load since I restored it was about 5000 lbs and all that did was make the ride noticeably smoother. I have never noticed a bounce in the ride empty or loaded and never thought about the need for shock absorbers. I doubt it would hurt to add shocks but from my perspective there may be other things you will find are more important to make your truck more enjoyable. Good Luck and keep us informed.
Kent
