It is a Manchester tank on my 1999 Roadtrek, and I would imagine it is so for all of the vintage Roadtreks. But I do not think that Manchester is making those old models of tank anymore, so I expect the only way to get an exact fit would be buying one of the expensive tanks from
www.mobiliferv.ca. Perhaps a similarly sized Manchester model with new brackets welded on to it might be made to work? I would be interested to hear if any RT owners have tried this.