Uh-huh.
Armour indeed went out of fashion among hoplites around the Peloponnesian War... and then came back into fashion. IIRC, in a somewhat heavier kit than previously too.

Around the same time hoplites (and other Greek soldiery) were also increasingly becoming full-time paid professionals if not outright mercenaries, and of course the elite formations (epilektoi) quite a few of the major communities had over the years - the most famous likely being the Theban Sacred Band - were naturally very well equipped and highly trained.

So meh.