Unless there is something about the person you are buying the gun from that causes you to be concerned, I wouldn't worry about it. If I was concerned about the guy, I wouldn't touch the gun.
The only paper trail a gun leaves in Texas, is when it travels through a dealer with a FFL or when the cops confiscate it. Finding which dealer a used gun went through is almost imposable. They would have to go to all FFL holders and check all their records looking for that one gun.
With a gun that was made after 1968, its easy for them to start at the manufacturer and trace it to who it was first sold to. After that its like looking for a needle in a hay stack.