We are in the same boat with our 2017 Forester 2861DS on a Chevy chassis. The Forest River Class C Motorhomes Facebook page posted a picture of this entertainment center and I posted a question asking about storage behind the TV and the response was that there is no storage there.
I did remember reading this thread:
that includes a picture of what one of the mounts used for these entertainment centers looks like and mentions that there is no way to get behind the TV to service/replace cables because of the way they had trimmed in the TV unless the entire cabinet system was removed. Maybe we have to install our own door inside one of the side cabinets to get to it......