Hey Shannon,
I don't think pine sap glue is necessary for mounting stone points onto arrows. It helps, but it isn't absolutely necessary. I've mounted points without pine sap glue and the sinew was plenty strong enough for that. However, I'm sure they could have gotten it through trade from other tribes farther south.
Also, I have seen sap from the Black Cherry tree that has oozed out of mature trees and dried....and it is VERY hard. When fresh it is like clear or amber jelly and it's very soft. But when it dries it's rock hard like epoxy, and although I've never tried it I would like to get some, heat it up, and try melting it and using it to mount points. It just might work. Something to try...