Kurdish Javelinmen and other true skirmishers do throw their weapons, but units with FAW off do not throw them at all. Siege units do shoot though, despite starting with FAW off.

I noted this a long time ago when I was fighting some rebel Hastati in RTW. They never responded to my own Hastati throwing their pila.

Then I came here but there wasn't much response to it. I guess I should have posted a new thread for it.