I keep going back in my mind to thinking that this perhaps wasn't a club stamp. A stamp saying 'paid' seems like something you would have at a store at that time. My father certainly used one still when I was a teen (1990s) to stamp records of customers having paid for the item in full. I would believe that this would not be something used by a professional club but perhaps by a person having a private party but perhaps having an entrance fee to pay for beer or something like that and the stamp was really for a business. I would really like to see a picture of the stamp mark to see what type of stamp it was...