Paulo, you posted the same picture of the obverses twice. Did you mean to also post a picture of the reverses?
It's challenging to assess from a frontal group shot like this. I agree, though, that the edges on some suggest casting. Whether the others - the ones for which we can't see the edges clearly - are genuine is impossible to tell. The lot could be a combination of legit coins and stinkers. Is the seller on the fake sellers lists?
Those marks are concerning to me, Paulo. So are the following.
I hesitate to condemn the lot without better pictures of each coin, though. I suppose some of these issues could just be reflections or irregularities in the edges of the flans. Can the seller send you detailed pictures of edges?
Looking at the reverses, if there were fakes that would be a heck of a lot of different dies. And the reverses are all really different in terms of artifacts, scratches, encrustation. Considering how many of these are are left on the planet, and thus how little they often sell for compared to other Greek drachms, it would almost cost an artist more to make these all differently then to just buy real ones. I heard stories these were still used accepted as currency well into modern times. The guy should just take edge photos for you and that would settle this fast enough.
If they are fakes someone with through a lot of trouble to produce different dies. As Bob has pointed out there are a few that raise questions. For the most park without having them in hand to examine more closely I believe they genuine, with possibly one or two fakes seeded into the lot.