Hmmm . . . an inventory number perhaps for an agency?? As suggested - post it on the Colt site - perhaps someone over there can fill in the blanks? Interesting . . . . I hope you'll keep us posted on what you find out. Looks like a nice piece - congrats on your find!
If a pair of '51 Navies were good enough for Billy Hickok, then a single Navy on my right hip is good enough for me . . . besides . . . I'm probably only half as good as he was anyways. Hiram's Rangers Badge #63