From what you have described as missing, aside from the upper sideplate screw Numrich seems to have all the parts you need in stock here:
MILITARY & POLICE. Accessories | Numrich Gun Parts
Certain current S & W models have the upper sideplate screw, no idea if it is the same size and thread type as the old one but a call to factory customer service may answer that question. Good luck in the restoration and please post the "after" photos.