From reading the equipment section it seems that the OGL Ancients book is designed for campaigns run between 600 and 500 BC. If I wanted to run a campaign in an earlier time period (say before 1000BC, which is when Egypt started getting occupied by each of their neighbours in turn) will it alter what equipment is available? What else will it change? When were the epic ancient legends and stories set (like Jason and the Argonaughts, Heracles, etc.)? What time are other GMs setting their OGL Ancients campaigns?
The equipment provides for a range of possible settings. I don't know the Egyptian (it seems pretty much Bronze Age to me, with the Man-Sized shield dating to the Early Bronze Age) but there's Greek armour in there which won't be available after the Bronze Age, like the Boar's Tooth Helmet and the Figure-of-Eight Shield. Sarissas are included but they don't get invented until the 4th century. You have to read the entries and note what's in use in the time period you want to set your game.
The Greek myths were sort of back-dated by the Greeks themselves, based on mythical genealogies, to c1150 and before. One traditional date for the Trojan War is 1184 or 1186 BC. But they also assumed and backdated a reasonable amount of things from later times... like Theseus was supposed to have made Athens a "proto-democracy", and vase paintings showed the Trojan War heroes wearing hoplite equipment which hadn't been invented at that time. They're really not set in a historical
period so much as an imaginary past.