It is very hard to tell these sigloi apart.
Hill has a short
work on them,
Imperial Persian Coinage, that might
help. He refers a lot to Babelon's
work on these coin, which is titled
Perses Achem, and is most likely in
French.
From what I can figure out, I think the
siglos that you have posted is either from Artaxerxes I or Dareios II. If can not be later than these two rulers because the fold in the
kandys takes on a V shape on the front of the
king with Artaxerxes II.