We owned a 2001 Rexhall 39' Aerbus with a Cummins ISC.
It was called a 3955
You can go to NADA and put in the info for that year and it will return all the possible models.
As far as I could tell, it was identical to a Roseair, except for the colors.
I have loads of technical e-files on its systems. IF you send me a private message with your email, I would be glad to send them to you.
Revolution LE 38X C9 Cat
2011 Scion TC toad