Yea, but fingers and brains are not strongly correlated. An evolving alien sentience could end up with just about any number of fingers, but most life on Earth has some form of symmetry or other making even numbers more likely. Thus I a can imagine that if we canvassed the entire galactic population, every civilization would use even bases, but there would be no clear bias to 10 in particular. Perhaps a bias away from really large bases, but not one that is in favor of 10 specifically.

I would not discard so easily that brains and fingers are not correlated, I know corvids, dolphins and other species show some level of intelligence but it's nowhere near humans so they are not in the same category to draw conclusions, so the only sample we have is humans, so until we have another sample I wouldn't make any affirmation one way or the other; also we know our advanced tool usage was not only develop due better brains but also due having opposable thumbs.