His mom mentioned them. Why isn't that good enough?
Because Noonian was said to have "lost" them? B-4 may look lost, but that's probably not what Juliana meant, and if Noonian had access to B-4, he would simply have continued to work on it.
Of course, B-FOUR
is a bit suggestive, too, if there were three
failed prototypes in evidence.
But it's the bit where they open fire on the Kolarans which doesn't strike me as being particularly right.
Well, Worf is probably firing a phaser. So for all we know, a direct hit at a local would only have stunned him!
We've seen phasers at apparent stun setting achieve interesting things such as cutting through metal ("Legacy"), so this setting overturning an enemy buggy need not be a contradiction. OTOH, Worf could probably toggle...