All Motorhomes are built on an Incomplete Chassis. I think the only ones that are not are Bluebird, and Prevost. all others are on a mass produced chassis that comes from one of the big 3, or a custom chassis company affiliated with an OTR truck manufacturer. Freightliner, and Spartan are the two I can think of off the top.
No worries, this is normal in the RV world. Every motorhome is a custom hand built machine. They NEVER make them exactly alike.
WBCCI #5501 AIR # 49
1978 Argosy 28 foot Motorhome
Wise men talk because they have something to say; fools, because they have to say something. -- Plato