Probably going to be hard to find and easier to copy. Given that Chris was making large wooden as well as steel and aluminum Roamers through 1968 and sometime later you might see if any are the same or reasonably compatible. This would give options for boneyard searches as well as Roamer and Constellation groups.
Good luck Tim
Chris my 45' has the helm chair but I'd like to scrap it and add a bench. Do you mind snapping a few photos of yours from the front, rear and side? Glad you made it through the storm unscathed.