Can an officer refuse to let you see the speed reading on his radar gun during a traffic stop for speeding in the state of Texas?

Without knowing the Texas law specifically, I will say yes. First if you had a 'right' to see the radar, he would have shown it to you. Second, most officers are taught NOT to lock the speed on the radar. It doesn't prove anything because a locked reading could have been locked in days ago, and it stops the officer from gaining more information. For example: I'm working radar on a straight road where I can see the cars coming at me well before they can recognize that I'm in a police car. If the person is over the speed limit all the way up to the point that they recognize my car and then jams on the brakes, that tells me that they KNEW they were speeding. IF they continue without overreacting to me, then there is a good chance that they are making an honest mistake and do not know the speed limit.