It's an "R" frame "O" grade extractor gun dated 1912---last year of production. Most-but not all had this engraving pattern. Likewise, this grade was advertised as Damascus steel tubes but could be ordered with London steel tubes.

Great finds. I am particularly fond of Parker Trojans. I've always liked them. I just bought a 16 that I'm in the process of restoring. I also am very fond of the early LC guns. Yours looks great. Congratulations.

I would guess 0 grade too.