^The movie made it pretty clear that B-4 was very simple and incapable of the kind of growth and learning that Lal showed. I mean, that was the whole thematic point behind the character.
Sure. That in itself doesn't preclude the possibility that he was the fourth prototype of six: B-4 did demonstrate reasonably advanced language and cognition skills, and it's imaginable that the previous three were significantly less functional.
Elias Vaughn wrote:
I think Mack should throw a curveball and upload Tasha Yar's brain into B-4.