Herb, if the CSR for your ancestor shows him returning to duty after 19 days, amputation was not involved! However, there were many more battles after Sept. 15, 1862, and it is possible that he suffered another serious wound at a later date. Although there are many cards in this man's CSR, it doesn't necessarily mean that it is complete. I would be inclined to leave the family history as is unless further information is found.