Nice revolver! In my opinion as someone else stated above, it looks like this one "sat around" at Colt for a while before shipping. The approximate build date per the serial number is 1884, and it shipped in 1890. My Manzanares-shipped etched panel is a fairly close serial number to this one, and it was built in 1884 and shipped in 1887. Several of the Colt books discuss cases of revolvers sitting around occasionally, with "late" shipping dates.