If I read it right the numbers after the SXS500M are type codes. My 2015 to 2018 service manual list the following: 2015 - 2017, AC, llAC - USA (50 States including California), CM, llCM - Canada, Australia, New Zealand. After 2017, A, llA - USA (49 states except California) , Australia, New Zealand. AC, llAC - USA (50 States including California). CM, LLCM - Canada. I believe the ll can be the number 2. Example: llAC = 2AC. The labels are located in different locations from year to year.