Both 2500 and 3500 have GVWs over 10,001 lbs. They both could qualify for being a commercial motor vehicle depending on your state regs. You can order a 2500 with the option CGO that restricts GVW to 10k and GVW to 26k.
GCW of 2500 crew cabs is over 26k so you could require CDL if you pull a trailer rated over 10k and are considered a CMV.
GCW of 2500 crew cabs is over 26k so you could require CDL if you pull a trailer rated over 10k and are considered a CMV.