Recall letter I got says 'for now don't use' AND that a 'second letter will advise when parts available for repair'.
Regardless, it's a 2 stage deal, and we should be notified when parts become available.
I expect them to do it by region as more and more parts are produced.
(no need to wait until enough parts for all have been made to start the process...)
2018 GMC 2500 L5P CCSB 4x4 Denali - Mineral Metallic; previous '11 LML, '10 LMM and 04.5 LLY