Looks good to me but I'm not sure that the style matches the Sept. 64 date. All the signatures also look quite carefully written using similar pressure. If it isn't real I would think it is an expert forgery rather than a secretarial or fan example. Without authentication or universal support from this group I probably wouldn't buy it for big money but if I saw it at a flea market I might take a chance, especially with any kind of plausible back story. Below is a group I own from earlier in 1964 for comparison. I'm pretty sure all signatures were written in an autograph book and sitting down (i.e. not rushed or written on an uneven surface).