The third water bottle mounting below the downtube and those great long chainstays certainly say 720 on 'em. The paint on the OP's bike is not that deep metallic imron that is on dziehr's bike...matter of fact, it looks a lot like powder coat to me. That would explain the lack of a serial number.

At $100, this is probably one of the best deals that Old Surfer will ever make on a bike.