A grade 5 Smith gun stamped 3" long range on the barrel flats would be real unusual given that the 3" "Long Range" and "Wild Fowl" models weren't introduced until after Winchester came out with their 3" shells in the early 1930's. If the stamp is original; then the barrels were replaced or rechambered (maybe by the factory ?) at a later date.
As to your stock repair, I just had a PE stock in pathetic condition repaired by a gentleman named Bill May; I was amazed at the result. His office telephone number is 205/348-9156.