No. Because they have already been current members of Professional Artist (GOLD). The new requirement for letters of recommendation will apply to new applicants (or re-applicants after leaving WAA). As long as the existing members remain the members of the Professional Artist of WAA, then:
1. They do not need anyone else to write letters of recommendation for them at WAA.
2. On the contrary, they are eligible to write letters of recommendation for new WAA applicants if they want.
Of course, new WAA applicants can also ask their country (or other places) internationally renowned (world-famous) artists recognized by WAA to write letters of recommendation for them.