Hello Paul,
Catalyst 6500 provides Supervisor redundancy with SSO and non-stop forwarding with L3 protocol HA capabilities. You should enable NSF capability manually based on L3 protocols you are using between Catalyst 6500 and remote system. Just make sure the peer device is NSF-Aware system so that during SSO switchover the L3 protocols can gracefully restore routing adjacencies and database while protecting fwding plane on each end...
thanks,
rahul.