Jim Morrison Sketch

Hi , I purchased this sketch about 6 months ago of Jim Morrison from The Doors .... I have tried to find something similair on the internet i have scoured google images,ebay,tons of rocknroll forums,a few art forums etc. and have yet to find anything even remotely close.

From what i can tell it looks like a charcoal skecthing but what i cant tell if it is a reproduction or an original , I havent taken it out of the frame its in which has a screw locking mechanism on all 4 corners. It is very neatly done , It has a "rule" insignia on the bottom corner but thats the only type of marking i can find .

I'm just looking for basic information on this right now till i get a chance to take more photos , i would greatly appreciate any insight or information anyone could provide - btw i know its not very new

thanks in advance