The authority on these is John Gyde, he'll probably respond later but the "OX" would indicate July 1929 as the manufacture date. I have never seen a nickel plated Model 12, anything is possible so its best we wait for John or someone else that knows these guns better. An octagon barrel does suggest it is a Model 12C.
Jim Peterson
Charlotte, NC
Trying to identify Remington Model 12
Re: Trying to identify Remington Model 12
Jim Peterson
Re: Trying to identify Remington Model 12
July, 1929 is correct. Rem offered partial or full nickel plating as an option on the M/12. Most that I have seen were earlier than yours. Talking from memory (dangerous thing to do) I believe the nickel was actually chromium.