Rear Wheel bearings - what type?

Thing is, All I can find is A7LK. For example, I checked the AutoZone site (there a number of them near me) and they list both A7LK and A7Rk, but they only stock the former. Same with every site I check.

Now, I can't think why you'd need a left and a right (what could be the difference?), but if they list both, I wonder.

Any comment?

~Bill