Chinese bad-dery clamp

I've been playing with cars for 30 years and never knew there was a difference between pos. and neg. clamps.
I know the battery posts are different sized. Just assumed the ones that were too big, as above, were …….I dunno. I just used what I had handy, and half the time I found the correct one. Do auto part stores sell Positive and Negative clamps?
My dart has the original cable integral with the terminal.