Yes, from what I have seen they are a branch campus as Galveston and others. Interestingly, they will begin with ~80 Engineering majors in general fields such as engineer technology and so forth. I think it is a good move for the university.
By chance I drove to Tres Lagos today for business reasons and went by the building. Calling this site A&M-McAllen is a stretch. Way out north of town. Like building a campus in Snook and calling it A&M-Bryan.