David,
I normally don't consider the standover height of a frame and don't normally measure it. So I don't know realitive stand over heights run far a given frame size. The bike may have been designed as a SoCal criterium bike. A high BB would have been the standard proceedure at the time. Bike mau have a relatively steep seat tube angle. It may have bigger tires than the original design called for. Could be a lot of things. May be the standover height is not measured correctly, who knows? Without the frame in front of me there is much I can not tell you.
Brian Baylis La Mesa, CA
Please note: message attached