Texas deadbolts?

[Rick Reed]

I'm closing on my first rental property tomorrow. The first thing I want to do after closing, is change the locks. I've heard that in Texas, a rental must have a single sided deadbolt (where the deadbolt locks ONLY by means of an inside lever). Is this true when both a deadbolt and locking knob already exist? I ask because neither of the exterior doors currently have such a deadbolt and the property has been rented out for some time.

Thanks in advance!