Is this "*MODELS/ACTORS*" advertisement a scam or is this a real opportunity?

Well... I suppose it could be for local student films or something, but big name movies really don't go through the newspaper. Occasionally they will do open casting calls for actors if they want an unknown (although lately, with some of them I have to wonder...). They usually go through agents for all the main actors, and local calls for extras. Modeling, I have no idea. I'm in the film industry, not the model industry. But unless it's for a new talent agency - which, as you mentioned, it doesn't actually say - it's probably a scam. I've never seen a casting call that is so general and has no information. The only time they are that general is for movie extras.