BIG (40" x 33" & 54" x 38" w/frame) Grateful Dead Poster w/Rick Griffin 1969 - Real or Reissue?

I found this at a estate sale today - the poster alone is 40 x 33 and with the frame 54 x 38 - it has Rick Griffin 1969 in bottom left corner.
I've found 1 even larger 48" tall one that I think was a 2nd issue (I've looked at a lot trying to find one like mine!) - is mine an original or 2nd issue?
There is no Printed in ... or any other identifying marks except the Rick Griffin 1969 that I could find.
Any information would be appreciated - there's a big difference in value in earlier issues!
Thank you!

 

It looks like the original advertised the Dead at the Avalon Ballroom. Yours does not seem to have that info along the bottom.

The whole treatment of the bottom edge looks different.

 

Have you taken it out of the frame? There should be a white 1/2” margin with a little peace sign and an anarchy symbol in the lower right corner. It might be a good Aoxomoxoa subway poster.

 

No just got it today & wanted to check here before doing anythng that coud hurt it

 

I just looked up Grateful Dead Aoxomoxoa subway poster and realized the black around the poster is part of the poster & not the matting for the frame - Now I have to try to open it to check if it has the symbols anundverkaufen suggested.
moreotherstuff if it's a Avalon Ballroom poster would it have something identifying it, too?
Thanks!