I ordered my 2018 with dual alternators. I snow plow and have a 9.5' Fisher plow which is why I went with two alternators. These larger plows are quite demanding on the electrical system. I don't see many ordered with two.
2018 GMC 3500HD L5P Denali, Fisher 9'-6" VPlow, 295/65/18 Goodyear Duratracs
SOLD 2006 2500 HD CCSB, LBZ/Allison, 285/75/16, Idaho Rob DSP5 Tunes, All Seasons EGR Full Delete, Pro Fab Down Pipe , All Seasons PCV Re-Route, MBRP 4" Turbo Back Exhaust, Nicktane CAT Filter, ARP Head Studs, AirDog II 165 Type C HG's, Updated DS High Flow Exhaust Header