curious about markings on pre-70 colt

[warddc]

I have a colt commander from 1965 chambered in 38 super ser no 48XXX-LW. It has several markings on the trigger guard that I have always been curious about. The first mark is a '0' in the upper right corner of the trigger guard when viewed from the right side. The second is an F' (that's F apostrophe) in the upper left corner of the trigger guard when viewed from the left. The last is a triangle with something inside the triangle at the bottom right of the trigger guard when viewed from the left. These marks are all stamped into the aluminum.

Any colt gurus have ideas?

dave.

 

[Old Fuff]

The "triangle" is Colt's "verified proof†mark, which shows that the pistol passed proof testing. A letter "P" is part of the mark.

The other alphabetical letters were made by inspectors as the gun passed through the manufacturing process. Who they were I can't say because over the years the letters were assigned to different inspectors.