Sorry that I can't answer your specific question, but it's been my experience that no standard sheet sizes fits Rv beds. If you (or a friend) own a sewing machine, it's easy to make fitted and top sheets from old bigger sheets out of your linen closet. I used a couple of kings to make both fitted and tops for the "twin" beds in our rv. Search the Internet for instructions and take good measurements.
2017 Class C Forester 2371 Transit Series
Hubby, Craig, and Miniature Poodle, Beau