In arcade games I've worked on, there tend to be only two different size locks: short and long. They have the same diameter, flats, and square for the cam... the difference is the length of the threaded housing. I think they're commonly known as 7/8" and 1 1/8" , but I'm not certain exactly where that length measurement is made.
Yours looks like a 1 1/8" to me. You can often find this type of replacment lock at hardware stores.