Anne, Fenton glass is not my bag at all, but for what it's worth - Fenton's hobs on their hobnail pieces are more "pointy" than the ones on your pretty jar. Other makers did Hobnail patterns - Duncan and Miller, Anchor Hocking, as well as some English companies.
Check out the hobs on this piece to see what I mean.
I may be all wet, since I don't often pick up Fenton, but I'm sure another US glassie will be along who knows more.
Kelli