Back in January 2024 Rivian added to their maintenance schedule a "Comprehensive Inspection" (in addition to tire rotation) at 22,500 miles. See
https://www.rivianforums.com/forum/threads/rivian-recommended-maintenance-schedule.23202/
A description of the items to be checked was posted on the...
My impression is that R1T Launch Edition vehicles have mostly been delivered at this point, and that R1S Launch Edition deliveries are well underway to be mostly completed by the middle of 2023.
A noticeable exception is for deliveries to Canada, which only recently started receiving vehicles...