here we go... I'd never heard of the Carri-go until your post so I did a online search and from the ones I found I'd say they are clearly Class C motorhomes. Some companies that sell this STYLE of Class C's market them as a B+.
The manufacturer started with the cab and chassis as supplied from whomever and built everything else. They chose for this mh not to include the cab over bed area but instead built a more streamlined unit with either storage or entertainment areas above the cab. The RVIA website states that the bed over the cab is an optional feature.
You can call it a Class C and be technically correct. You can also call it a B+ and folks might more readily know what the unit looks like.