2015 RZR XP 4 1000 Roof and belt questions

Hey guys just bought a 2015 RZR XP 4 1000, had a two seater 900 prior. Wondering if a 4 seater 900 roof will work on it. There is a few on ksl.com for a good price. The other thing is the belt, I was told it had some new carbon fiber belt on it can’t remember the brand he said. I started taking off the cover due to I noticed a lot dirt in the clutch cover tube and there is a Gates G-force on it, in fact its the same belt I ran on my 900, part # and everything. I was told the belts don’t work on the 1000 by the prior owner. I took it on and off to make sure, even put it up next to my 900 belt. Can someone clear these things up for me please and thank you.