I installed a swivel seat base on the passenger side of my 2006 Itasca Cambria using an OE [but sold thru JC Whitney & Co] Ford swivel pedestal seat base. Works just fine & in my case was almost a true "bolt-in".
I think if you can find an example of a swivel seat base installed in another [manufacturer's]version of Winnie's Navion/View, it too will fit your application.
However, you aren't likely to get much help from either Winnie or a dealer to do the installation because of [presumed?] warranty, DOT, safety, etc., concerns.