Were warships already divided into formal rates?

Were warships given formal ratings at the time of Kentish Knock?

Only in an emerging sense: ships were being distinguished by fighting value, but later formal rates and line-of-battle exclusions were not yet fixed.

The 1650s were a transitional period in warship classification. People distinguished great frigates and ships intended for battle, but the later, rigid rating system had not yet fully defined which vessels belonged in the fighting line. Because fleets still relied heavily on converted merchant ships, vessels carrying twenty-four or twenty-eight guns could enter actions against opponents with twice their armament. The answer warns against projecting Nelson-era categories backward onto a fleet system whose organization and tactical expectations were still developing.