M915, M916, M917, M918, M919, M920 are an AM GENERAL product and cabs are made by AMG.
M915A1 is a CCC manufactured cab for AMG.
M915A2, M915A3, M915A4, M915A4R1, M915A4R2, M916A1, M916A1E1, M916A2, M916A3, M917A1, M917E1, M917A2, and M917E2 are all Freightliner Cabs.
M915A5 is a Western Star...