PICASSO's "Goat Dance" or "Dance with the Goat" ORIGINAL or NOT?????

I purchased this Picasso that had been in storage for many years. The glass was broken, and is dirty. The frame is the right silver, plain frame. The paper has the correct dapple. The ink shows no dots. The edges have a slight irregularity, I believe the result of printing on the dappled paper. The patina seems correct for the age. The signature, and date are unique to any that I have researched. The story is of someone who lived on the upper east side of New York, long since deceased. The paper measures 33cm. X 40cm. How can i tell if this is an original print??