Several rifles have been rebuilt, Primarily Vietnam era rifles. Commonly the barrels were changed. Some examples of markings located on replacment barrels include things like: If it is a bell form, that could be correct for the Colt. As well as the fuel tube coloration and texture is appealing. See https://caidenssrqo.empirewiki.com/8505383/colt_python_6_for_sale_secrets