What on Earth is this Stuff on The Roof???

Hello Sunline Fans,

So, I picked up a "new to me" Sunline T1550...and I'm
making plans to shore up the roof a bit.

It doesn't have any visible leaks, but I intend to use it as an Office in the
backyard and want to be sure I don't develop any leaks this Winter.

I've emailed back and forth with Dicor and they believe I should strip all the black/grey stuff -- (including all the "flaps" around the Skylights and Vents).

But I'm not even sure what the material is. In some parts it looks "brushed on" and in other parts it looks like a SHEET of some kind.

I made a little Youtube video to send to a local RV Roof place (Quote was for $3,300!!! Yikes!).

Anyone care to take a peek at it and see what you see?
https://www.youtube.com/watch?v=hfehHfT3nLw

Just brainstorming and looking for best ideas.

I kind of like the idea of stripping it off and starting with the Eternabond Tape all around -- and then maybe the Henry Aluminum Roof Sealant or the Dicor -- though some of those reviews online are pretty scary with regard to adhesions issues.

Anyone want to see a messy roof? ;)

Thank you all!

Mark in Massachusetts