I have a 2016 28RBDS, may have the same tv mount as yours (?).
The one that came with the trailer was a very small cheap mount that was difficult to get to. It has a small latch you have to push up on then the TV can be lifted off the mount. I had to get my arm behind it (tight fit) to reach the latch. I could not see it had to feel for it.
I had a 31" installed, pulled it out and put in a better mount and a 39", you will need to measure the opening (diagonally).
The TV was installed by the dealer, so a factory mount TV might be different.
One good tip from a tech I talked to was to use 3/4" screws for the mount. That way you don't punch them thru the mirror that is on the other side.
2016 Jay Flight 28 RBDS
2015 F250, 6.2L