I am guessing there is an "owners manual" that covers every trailer Keystone made in the last few years that came with your camper and has a disclaimer in the small print that allows Keystone to make product mods without notice. Say the Cougar you have doesn't have that TV frame... that is the sort of thing they usually leave an out for. One drawback of a framed television is the angle for watching likely can't be changed. If you are lying on the bed, with the framed tv, you probably can't tip it downwards and will get a stiff neck trying to watch...
You might have better luck buying an aftermarket frame:
https://frameittv.com/tv-frames-2/