The information posted here in response to your query about serial number identification is quite accurate. The 'Serial Number Range' B.S. is exatcly that. I have examined some National Archives reords of serial numbers for M1860 Colts, New Model Remingtons and M1863 Sharps Carbines issued to one Company of Union Volunteer Cavalry and in the case of every weapon type the gaps between recorded numbers is broad enough to be able to dismiss the notion that it is likley that closely associated numbers likely went to the same unit.

To help answer your question about the M1851 Navy, you probably should disclose the serial number, at least in part. The government did not purchase any M1851 Navy pistols after the late 1850's so if you have information about a gun 'identified' to a CW unit, it was likely a 'hand me down' and if it has proper inspector markings, etc. might be able to be traced, but probably not.