I'm not good with that but it would be nice if you had a breeding pair to get more cb on the market, did the person that sold them to you have any input on the sex
Whether a pair is combative is not a good indicator of them not being a male-male pair. These types of interactions vary tremendously between individuals and can take a long time to materialize, if they ever do.
The best way is to look at the tail base for hemipenal bulges, but it can be very difficult.