I didn't receive an email, but while replacing the MCU the Service Center replaced mine, following is the description from the invoice. For the MCU replacement I was given a loaner so can't comment on how long it will take them to replace the airbag.
Concern: Replace Front Passenger Airbag
Corrections: Replace Front Passenger Airbag, 2013 Model S
Replace passenger front airbag. Completed
Parts Replaced or Added
Part Quantity
MS NA - PASSENGER AIRBAG CAMPAIGN 1 KIT (1118926-00-A)
Pay Type: Warranty