Been there, done this...
You can apply just about anything you want over the existing wallcoverings--be they "board" or vinyl "wallpaper."...even countertops. It only requires the right prep to the existing before applying the new, and materials intended to be used over old. Skimp on the prep, or try to save money by going with an inappropriate material, and you won't be happy with the results...but do every step meticulously, and the result will be indistinguishable from factory original.When I decided that the '70s "harvest gold" countertops and wallcoverings on my boat had to go, I put new vinyl wallcovering over the old...got everything I needed including instructions from Sherwin Williams. I've posted the instructions within the last few months...so you should be able to find 'em if you search the archives for "wallcovering." New "formica" veneer went down over the old galley countertops...I had a pro do that. It's labor-instensive...not a job you can do in a day, or even just a single weekend, 'cuz each of the prep steps have to "cure" for at least 24 hours...but worth every bit of the effort.