I'm afraid this is a question for which there simply does not exist sources to address. However, the city-states of Ionia (western edge of Asia Minor) were under Lydian dominion and were probably at the time the center of Greek intellectual life, with philosophers like Anaximandros (who died around this war) and Heraclitus (yet to be born). It has been argued (discussed here ) that Ionian philosophy shows signs of influence from Iranian tradition, but this probably also came from interaction with the Medes prior to Cyrus' invasion. Consequently I find it unlikely that the Persians were a wholly unknown quantity before Cyrus' (poorly attested and myth-filled) conquests.

"Persian culture" was also something that had to develop and adapt to meet the demands of empire-managing, including the rapid urbanization of western Iran. Thus it was a very non-static thing and the question becomes a bit ill-posed. We do know that the Greeks weren't great at distinguishing the Persians from previous hegemonic peoples like the Assyrians and Babylonians, though.

It should be noted that much of what we think as highly characteristic of Greek city-states like Athens was also something that was rapidly developing at the time, and would evolve from contact with and in reaction to the Achaemenid Empire.