Congratulations on an awesome deal!! If you haven't already, you may want to check the Singer serial number here:
http://www.singerco.com/support/serial_2letter.html I'm fairly new at identifing the vintage Singers, but that might be a Singer 15 rather than a 66. I just got one from a friend & will be using it for my FMQ machine, partly because you can lower the feed dogs on the 15. (Don't know about that on the 66)