In our travels we've found that CG's that offer GS Discounts also more often than not also offer the same discount to AARP members as well as active/retired military (including veterans with DD-214). Had a CG in Oregon two years ago that gave me both GS and Retired Military discounts!
'07 K3500 Silverado LT Crew Duramax (LBZ)
2016 Salem 27RKSS
1984 CHEV SCOTTSDALE K20 2GCGK24J0E1XXXXXX (Chevrolet Legends-Class of 2019)
"...exhaust fluid? We don't need no stinkin' exhaust fluid"