trust me i know how you feel. sorry i cant give you an opinion on the sig but obtaining one of my 3 dream autos came true last month when i purchased a John Lennon Bag One litho (exotic one) with minor damage for $1500. I had to get it and so pleased with the purchase. Its a perfect looking signature
This is the style of signature John was giving at the WFML charity event in 1974. Not nice autographs really. As to authenticity, it's possible but I'm going to go with not authentic, it just doesn't seem to have any 'flow'.