You are correct on both things... yep more engineering ahead and only 60T chainring.
Yea many of them I have seen do have multiple holes on them, as to what model exercise bike this one came off of I don't really know because I bought it from someone on one of the FB pages I belong to.
Just keep your eye out for anything made of metal and see what it tells you it wants to be a part of. You may be shocked at what you find that you can build a bike from. For example I built the frame of a bike from a Reese hitch car tow bar.