You didn't mention this, but from the parts you need, I'm taking it for granted that your '76 is an original. Very few parts will interchange from a '73 to the '76. Wood and dust cover will not interchange. These parts, as well as the extractor and of course the carrier block are all specific to each model. Most screws will interchange from original 1873's to 1876's, most trigger parts are also the same and will interchange. I no nothing about either of the reproduction guns and whether or not those parts fit original models. I have heard stories from both sides of the isle. I do have a friend who bought some internals from Chapperal to fix his original 1876 and nothing would fit without major alteration.