Though I have extensive experience with Pace Arrow and Southwind, my knowledge of the Bounder will be generic. I can tell you that both the relay type isolator as well as the large finned diode type islolator were in use when your coach was built. I can also tell you your coach was built using one or the other? It's pretty safe to say you do have an isolator - or you did originally anyway.
You should be aware of the potential that whatever it was built with originally could be radically different than what's there now, though functionally identical!
If you can use a test light and or a voltmeter, there's no rocket science involved. It's pretty easy to figure out as long as you aren't shy about getting your hands dirty.
What, exactly, has you curious about this system? Is something not working?
1997 37' HR Endeavor, 275hp Cat, Freightliner
03 CR-V Blue Ox, Ready Brake