I've been doing a bit of research myself. My 1911 pictured in the OP was produced in 1918, as evidenced by the serial# 249xxx. That puts it in the first 300,000 guns produced, and prior to the Black Army period where the final polishing step before applying the finish was skipped to facilitate faster production. This accounts for some of the ~ 325,000 guns of the Black Army period (May 1918 - March 1919) exhibiting poor finish retention.
https://www.colt.com/serial-lookuphttp://www.militaryfirearm.com/Forum/showthread.php?19126-1911-Guru-s-needed-!!-1918-Colt
