Ah, but the Ilia probe was unfamiliar with Carbon units - the same carbon units that have always formed the basis of a Borg drone. If V'Ger was from the Borg, why would it be so unfamiliar with a core part of Borg physiology?
Besides, do you really see the Borg finding an ancient space probe with laughable technology and then they decide to be nice and help it out?
Thats why i said the Borg homeworld before
they became assimilation junkies. How do you know that the Borg have always used carbon units for their drones? The way they were presented in Q who its entirely possible they started out as sentient machines and only later converted organic lifeforms into drones when they began exploring space and encountering organic lifeforms. V'ger could have come accross the Borg homeworld before they had encountered any sentient organic lifeforms.
Besides that wasnt a serious theory just a funny coincidence that i noticed whilst watching the movie (though it probably is my own head fanon now :P )