MTV Grandfathering question

Looking at NVIC 02-14 I see the following criteria stated for obtaining a “grandfathered” master of towing endorsement:
Under 46 CFR 11.463(d), mariners who met the training and service requirements for
towing vessels before May 21, 2001, and have maintained a valid Coast Guard-issued credential may obtain the towing vessel endorsement if they:

  1. Document at least 90 days of towing service before May 21, 2001;

  2. Have successfully completed the Apprentice Mate (Steersman) exam, its predecessor exam, or an exam for endorsements authorizing service on vessels greater than 200 GRT. A mariner who holds or has previously held an endorsement for Mate or Master Not More Than 200 Gross Tons or higher, or as Operator of Uninspected Towing Vessels (OUTV) will be considered to meet this requirement; and

  3. Complete a practical demonstration of maneuvering and handling of a towing vessel to the satisfaction of a Designated Examiner. This may be satisfied by completing the maneuvering and handling section (“Part D”) of the applicable Towing Officer Assessment Record (TOAR).

Does item (1) mean that you must have held the Coast Guard issued credential since before May 21, 2001?

I would appreciate any clarification I can get on this.