frumpy, sorry for jumping in front of judy to answer but this would be an original. bonnie mclean was resident poster artist at the fillmore for a while in the 60's. PM's not here at the mo but she's bound to give you more info on it than i!
I believe the poster artist is actually Bonnie MacLean, who was the artist responsible for most of the chalk art fot the billboard at the Fillmore West.
Great submission, as this poster is not even included in the Art of Rock book.