Smith & Wesson Model 39 Eight Shot Double Action. First Year Production Variation Serial Number 1478. Handgun was shipped November 4, 1955. Shipped with a 4 inch barrel, with smooth rosewood grips, unfinished (in the white) to Rex Firearms Co. New York, NY
Picked up at factory by Mr.W Sanborn, Smith & Wesson salesman from New York
Rex Firearms used several contract engravers in the New York / Hartford, CT areas. Could be any one of them, no real way to know for sure unless you find initials somewhere on the gun.