I don't hunt south Texas and never have, but I have some buddies that hunt down there. They say that the rut lasts into the middle of January. You'll be there 3 weeks after the usually peak of the rut, and IME you should still be seeing some rut activity in that time frame. If there's a secondary rut it shouldn't have happened yet, so I would think the bucks would still be showing rut behavior. There's probably a better chance that some bucks may have broken times, but that depends a lot on the buck to doe ratio. If you have a lot more does than bucks than the bucks won't be fighting as much, but a ratio that is close to even would mean a lot more competition for does and more fighting. Good luck and hope you enjoy it.