Your 195RB is a "Rear Bath" floorplan.
As stated, there's no industry standard (unfortunately) for assigning model numbers/letters. Manufacturer's will occasionally use/try something "new/different" to distinguish their floorplan from others, but... overall, they're basically very similar from one manufacturer to the next.
Here's a previous thread which should be helpful.
http://keystonerv.org/forums/showthread.php?t=7454
Terri, the Chevy co-pilot
