Frank Whipple "tic Tac Toe" Nuns, Pencil

Frank Whipple "Tic Tac Toe" Nuns, Pencil-signed Limited Edition 454/1000. My grandmother purchased this print years ago, guessing early 1980's?  Truly not sure. She resided near the gallery in Morro Bay, CA (Parkhurst Gallery). I have been trying to authenticate that this is a true Frank Whipple. The artist's signature looks great on the print, and the one signed in pencil. The other photos on Ebay of this print show a green ground, but this one is clearly blue. Also, the "T" in the title "Tic Tac Toe" differ than others (the T's here match to the style of the signed F in Frank Whipple). BUT, I don't know if the artist changed the way he signed the title over time of the 1000 limited editions, or if this one is a "Fake", or maybe the others listed were fakes. The matting on this 9 1/2" square piece does have some warping, but the print itself is in excellent condition. The shrink-wrap is intact, and has never been removed, which probably caused the warping over time. I attempted to show the slight warping in two of the photos. Also, in the photos, there is an easel. This is NOT included. This listing is for the print with the matting only. I am trying to give as much disclosure as I can.  I am not an art expert. If you like what you see, please make a purchase, or please make an OFFER Thank you for your time to read this. Please take a look at my other listings.