No such thing as a Class A body on a Class C chassis. Either the chassis has a cab and the RV is a C or it came bare and the RV is an A.
Being bare chassis from E-series, or Sprinter, or G-series (some years ago) or F-series just means a oighter chassis was selected for a smaller A. Wasn't that long ago, 30 years, that many models of A gasser or front engine diesel came in at 10,000 to 12,300 pounds GVWR built on a chassis that commercially would be under a van, step van, or delivery truck.
RUV designation is a Thor marketing tool, trying to sell a RV as alternative to a large SUV (better target might be the conversion van) trying to convince you it is small enoughto be a daily driver. Not a RVIA category yet.