Too many 'things' happening with the framing elements , tagging & misc. to be definitive , IMO , on the on-line deal & agree that you're on the right track towards checking it out , corkysgold .
If it was in my sweaty little mitts , I'd have sliced out & removed the strecher-frame/canvas assembly by now (more tales may be told by uncovering that which cannot be currently seen) to have a good eyeball at it (or @ least one edge of it to take a peek at the canvas & edge elements) !
Don't be too shocked if it's a 'copy' , a multiple or etc. (even those can be worth some bucks) & that way you can have a bigger shock if a one-off , coreysgold !