It sure looks like AC to me. I cannot imagine what else it could be. Your coin clearly says AC, and I think this is an
obverse die match. The same letters are prominent, and the same areas are soft on the
legend. However, your coins looks like it has a better strike, but also shows more wear..
The earlier coin I posted seems to have
something in the left
field. I also see "AC" in that coin, but to me it looks like there was an attempt to merge the letters into the design so that it was not as obvious. Quite honestly, without seeing your coin first, I probably would not have guessed "AC" for that first coin. For the second one, I am sure it is AC.
But now back to the original question -- what could the AC mean?
Alexander and
Constantine? The Patriarch Antony Cauleas?