Yep, Frame number is sometimes beneath the left side tool and airfilter cover...at least on the '65 model.
What color and year did you pick up or have?
The blue and white seem to be less seen. I have a rough blue '65...need to sell it as I don't have the time to restore it with all the parts I have acquired for it and need the money quicker than I would be able to rebuild it/restore it. Not that they go for significant money. They are nice around town bike or leisurely cruise about the countryside.
David
David