steveoberly, are you sure you saw different items for cat6 rj45 connectors? The RJ45 connector is an industry standard network jack. The cable can be changed such as Cat5, Cat5e, Cat6, even your regular old phone able, can all be used with the RJ45 connector. Ive never heard of a specialty connector for cat6 cable. Reason being, is that the RJ45 is, as i said, industry standard so it fits into network cards and computer systems. If they changed the plug, then it would not fit into computer systems and networks.
So I think what you might have seen was a cat6 grouping with rj45 connectors included, but you will most definitly be fine using cat6 (or any Category cable) with an RJ45 connector.