SmileySSD,
Welcome to the QB.
Yes, it will sew. It just needs some TLC, and lots of cleaning. You've got some things sitting on the cabinet that don't go with it (the two shuttles), and it's missing the belt guard / bobbin winder, but that's findable.
Oh, and don't get rid of that Singer belt package, that's got to be an unusual thing to find.
As it is now it's a treasure and were it mine I'd make sure to get it all up and running.
PS (I'm a bit prejudiced for the Singer 66. I've only got 6 or 7 of them. Three of which are treadles. )
Joe