Here is a 1922 Commercial Colt which is featured because of its slide pitting (and what effect that will have on the lettering), as well as a contrast to the above 1913 Commercial regarding striations.

Steel improvements made during WWI pretty much eliminated the problem of striations found on so many pre-WWI guns, of all makes. Though I've certainly seen many pre-WWI guns without any sign of striations, there is a risk that these earlier guns can have the problem. Even if no striations are visible before the restoration, there is a possibility of striations developing during the restoration.

This pistol has Rem-UMC grips and a WWII magazine, but all other parts appear to be correct. It has a matching serial-numbered slide, with the SN under the firing pin retainer. The slide has the 'new' left side lettering, which is post-1919 and correct for this 1922.

Scroll down to view the series of pics taken during the restoration of this 1922 Commercial Colt:

The original Colt 1922 Commercial model (left):

The original Colt 1922 Commercial model (Right):

Left slide closeup:

Right slide macro showing pitting:

Left slide after some polishing:

Right slide after some polishing:

Left slide after still more polishing:

Right slide after more polishing:

Left slide with final polishing and lettering:

Right slide with final polishing and lettering:

A mockup of the polished gun with it's major parts; ready to charcoal-blue:

Completed pistol:

Completed pistol: