Can you identify these bucket seats?

[Blue'72]

I picked these up last night and was told they were from a motorhome, but not sure what year. In trying to identify them through googley images I came across an ebay add for a complete set with bracket and console stating they were 67-72 Buddies. Sure they will work as such, but I'd like to know what they may be from originally so I can get seat covers if I decide to. I searched and searched but haven't seen anything with adjusters and springs on the bottom like these. Unless the bottoms are enclosed with a cover? Thanks for any info y'all can provide!