Hmmm... wonders what happens if you remove the I_CompareCounter Romanii_Reform = 1 and get the Marians before Polybians, and then get the Polybians?
Anyway, in my best Romani campaign I got an Augustus at 218 BC, but since the Augustan reforms can´t actually happen until 125 BC I´m kinda out of luck. I mean, by the time I get those reforms I´ll probably have had like 8 different Augustus or something.