If I'm not mistaken, this is souvenir menu from Las Vegas Hilton Hotel (1975) and even with this secretarial signature it's cost about $150-250 on eBay (depends on condition of the menu). So this is good news for the owner of this item :)
Good news? Well that depends on how much Susanne has paid for it (if she has already bought it), or just wants to find out about the authenticity in advance.