One of a kind, not original poster but ORIGINAL signed cast AYKROYD - MURRAY - REITMAN - RAMIS - MORANIS etc. These signatures were made by an uncle of mine who worked in cinema from the 70s to the 2000s and he gave me quite a few authentic signatures before he died a few years ago! I don't have any certificate of authenticity but clearly the signatures are authentic as you can see from the photo, although I don't know on which occasion he had them done! They were made with a fluorescent marker that partially passed through the cardboard of the poster (see photo on the back)!
I have numerous other signatures of Hollywood actors this uncle of mine had done on publicity photos and various advertisements, and will be putting some up for sale as time goes on.