198670 markings help

[Stephen Glenn]

I would like help identifying additional markings on the barrel flats and lug of my Parker Trojan.

By serial number it was made in 1922. It is a 12 ga with 30" barrels on a size 2 frame with ejectors. Pistol grip with end cap and plastic? but plate.

On the one side of the barrel flats is the initials JC in an oval. On the other side is the initials OV and an HT over an A. The 42 is the barrel weight correct?

On the lug is a 2 indicating frame size. There is also a 12 stamped on the lug at a 90 degree angle from the 2, what does that reference?

Also, what is the chamber length? I don't see any markings on the barrel as with newer guns. Will it shoot 2 3/4" shells or do I need 2 1/2"?

Thank you for teaching me and on any information you can provide.

Steve