Yup lots of cowboy stuff in Playa.
There is at least one other leather shop on Cozumel that has shoulder holsters and hoslters for semi-autos...when you get off the ferry from Cozumel walk straight down the road in front of you and hang a right at the first street (PAST the big open park area, I think there is a bank on the left of that intersection). Leather shop is there in that strip.