I think they put an aluminum or steel plate in that area similar to
what they do with ski's. When the bracket is properly installled it
acts as a reinforcement to keep the bracket from pulling though the
paneling.
I would ask two things.
1. Do they say you can use a swing mount?
2. What kind of screws do they reccomend?
I would think the answer on the latter is sheet metal and to pre drill
tihe a body dia drill bit so they tap the panel and the metal
reinforcement.
I would also look at adding a narrow shelf the TV rested on when
traveliing and anchor points for a couple of bungee cords to keep it
pulled back. I like bungee's for that as they keep continuous
pressure the most strap systems do not. You also want an abrasion
buffer. A plastic trash bag usually will do it.
In a unit that size I would doa 20 or 22 in and save the bouncy
weight. the sight line is probably not that long.
All this is YMMV, and priobably will. ;-)