This one is a little out of my wheelhouse so i turn to the gurus! Curious about this Whizzer. I can possibly buy it. I know it sits on an early 50s Schwinn with what appears to be a nice complete Whizzer kit. What else do i need to know? Are there some engine serial numbers more rare? Is it complete? Anything glaring out to you? Ballpark on value? Thanks for any and all info!