Decadrachm Of Syracuse

Looks like it to me, I think I can see indications of lost wax casting.

First, welcome to CCF.

Second, I agree most likely a fake--the porosity on the face and even on the rim is the biggest indicator for me.

If someone complied a top ten of faked coins I imagine this one would be near the top.

@Finn - with lost wax casting you don't have an obvious casting seam since the mould has no join in it (a solid block of plaster of paris is used which is produced using the waxes and shattered after casting. The edges only tend to be filed to remove the sprue/sprues so sometimes there is a flat spot though since ancients are often irregular in shape this doesn't help us.

The wax models are produced from rubber moulds which are cut away from the real coin with a scalpel... this leaves fine hairline indentations as could be seen at the edge 10.30 on the first photo, the lines typically run around the edge but could also run across the face usually close to the edge.

I only know this from first hand experience cleaning up medals and jewellery cast in such a fashion though now with 3d printing the waxes can be printed rather than made from rubber moulding and therefore casts can be made with no such traces or seams...so your other indicators (pourosity/lack of fine detail) are far more important than relying on seam evidence.