The one with the 7 1/2 inch barrel is identified as Morgan Earp's revolver, and the 4 3/4 inch revolver belonged to Virgil Earp, and is identified as the gun he carried at the OK Corral. I'm including the notes by each gun, hope they are legible enough. The thumbnails do not do justice to the grips. Virgil's are undoubtedly ivory. Morgan's gun might be antler or bone with it's discoloration, but I am not an expert...it could be ivory as well. Whether or not the provenance is correct, they are a neat looking pair of guns. If you are ever in Branson, treat yourself to a meal at the Keeter Center on the college campus and a tour of the museum Students at this college literally work their way through to a degree and graduate debt free; pretty remarkable these days.