Depends on the size but if it has the same size as “Lords of the West” it seems likely.
I guess we’ll get three new civs to get up to 40 and 1 campaign for a base game civ. Adding 2 would feel awkward. Maybe we’ll get even 5, but that would probably mean a longer development cycle. It’s probably a smaller one.
Wait and see. If it’s supposed to be released then, I guess we’ll know more about it in 2-3 months.