Xlolobsterman
Good to see you are preserving the bike as it is, it is a piece of history in its own right and not to destroy it by building it up the riding it would not be a good thing. It can hang in a museum for its uniqueness, well until it is confirmed for its date.
I did measure and drew my frame in comparison to the Breezer frame of 1980/1 series 2 that is one the could have been copied by Schwinn,. Can you
check your frame and the Schwinn KS for similarity particularly the geometry. If Schwinn copied our Frame they have they could have copied it for the KS.
Well, Breezer and Tom Ritchie and say they used the 1940`s Schwinn frame geometry for inspiration. Mountainbikes recycled old 1940s Schwinn frames.
The quote below confirms that Schwinn would have been reluctant to say MTB and called the frames they made ATB. Schwinn backed off using the clunker name for similar reasons.
Les