What you can guess at is this: the Gieloth presence in Babylon is very strong right now, they've been growing unimpeded. There would be more than there are in Thebes. Furthermore, the ones in Thebes are Children spawned by Sekhenun, which you've been stomping without breaking a sweat for the past three years (no XP there since they're too low-leveled, sorry! But their sorcery is still enough to give a mortal trouble, and they might have other tricks up their sleeves), while there are definitely mature Gieloth in Sumeria, similar to Sekhenun and her sisters.
You don't know for sure if there are any marching with the army, but given how they've operated before, and that the Assyrian king was recently slain by the Babylonians, you rather suspect there are. You don't know how many, though.