I only bought right wing clamps because because right wing is the kind that's always been easiest to get at the local shops. I've bought arrows fletched left wing and they shot just as well as my regular ones. Sometimes I even thought they shot better.

Left or right doesn't really matter unless you're shooting a selfbow and using your hand as a rest. Then a rightie will need left wing and a lefty will need right wing. It helps prevent those nasty, painful feather cuts across the knuckle.