Use of Stainless Steel nuts and bolts has its own problems, if high grade Stainless is used(rust resistant) then these can fracture and fail under stress whereas mild steel will stretch. Also ensuring Stainless nuts and bolts remain done up is harder to achieve, although not impossible. Stainless could be used in most places on a Morgan but I would shy away from any major nuts and bolts retaining suspension, brakes and mounting brackets.