Of the 10,000 total Texas Ranger Commemoratives (1823-1973) made by S&W in 1973, there were 1,950 TRs that were sold as just the 19-3 revolver in the case, and 50 were Class A engraved with knife and case. The other 8,000 were the sets that included the 19-3 and the bowie knife with sheath (SCSW 4th Ed. Page 219). Since the s/n's don't match and you have presentation cases for both the revolver and the bowie knife, it sounds like you have one of the 1,950 that were sold as just the revolver and case, and a previous owner picked up a TR bowie knife and case separately (see SCSW 4th Ed. Page 472). There were 12,000 TR bowies sold separately.

We do need to see some pics when you can post them. I believe that you will be very happy with your TR 19-3! Enjoy!