I installed three mounts in my tt. There were no stickers indicating where a backer board might be. I was able to determine the locations with help from FRF members that had the same model tt as mine.
I used a stud finder and pushed in on the wall board and could feel the backer board areas. Your best bet is as Bikendan suggested and find someone with your same brand, year and model to ask. Maybe a dealer would know the location.
As far as mounts, I really like the Mor/ryde brand made for rvs. Very heavy duty and well made. www.morryde.com
,consumer products, tv mounts. I used two of the TV5-002H models they allow for quick removal of tv for travel.