Authentic Mesembria Thrace?

I don't have one of these myself; I did not find a match at forgerynetwork either.
The details on the obverse look similar to this one on vcoins--minus the wear.

Not yet. Roman is still my coin of choice. But some of these Greek coins can be very interesting coins.

There are three kinds of coins. Class one I know deep in my heart that they are good. Class two I know are fakes. Class three I am not convinced enough to make a big thing about it but I still have doubts. I only buy Class one. Your coin strikes me as possibly a fake. There are a couple things I don't like about it but the greatest is the heavy ridge over the eye slits. The big characteristic of the Black Sea Hoard fakes was that the die cutter made the empty helmet look a little too much like a face. I can not prove that this coin is bad but it rests solidly in my Class three. There are so many fakes of this type that I would not buy the type unless I were buying the coin as a fake for a fake price.

Well...that's interesting. Actually, my first impression was something looked off about the strike/surfaces, but I don't want to chime in every time I have an unseasy feeling. Still, I was curious if the coin was silver because the encrustation on the helmet doesn't quite look right either. I wasn't about to blurt this out if others liked the coin; I need to devise a "class 3 response".

jwharper: with your coin, is it possible if you can photo micrograph the edge of the coin?

If not, examine the edge of the coin, looking to see if it has been cast or composed of two halfs. See if there has been any activity of working on the edge to remove this type of evidence.

How much does it weigh? Can you bend it with your fingers only? I have discovered a few silver plated lead fakes in this way.
Where did you obtain it from? This type of evidence is required to establish provenance.

So far, from the pictures presented, the style and the whole coin looks OK to me.