Yes, it's cast cast signed. Looks like it could be real to me. They sure look signed by different people, and the ones I checked on HistoryforSale.com looked in range, considering.
Looks like some kind of trade advertisement, maybe from Variety or another magazine as some sort of "For Your Consideration" promo. The "signatures" are part of the poster design and are pre-printed -- no way that was printed with only the logo in the corner and nothing else on the rest of the plaster cast.