I changed both TVs in our first rig and added patio sliding door lock for locking in place.
I am in the process of finishing off the two boat anchor cabinets openings so they will look like the rest of the cabinetry. I will use the face frames for a mounting location. Everything I'm using to fill the hole is 3/4" oak.
I am going to pop for the very pricy mounts used in newer MoHos because they have a lock built in to hold the TV against the wall.
Lots and lots of acceptable mounts out there and for once I'm not going cheap, like the cheap mount for my 43" set in my office. $16.99 on sale at Harbor Freight.