The current spec on the RW site is 15088 Dry and 3152 Dry Pin.
So even loaded lightly the pin will easily be pushing 4K.
And as an example, our '16 39MB left the Factory almost 2K more than the published Dry weight. So I would guess that the 4001LKs will be easily in Dually territory with that pin weight.
Michelle & Ann
2018 Chevy 3500HD Crew Cab High Country DRW, D/A, 2016 RW39MB, Dual ACs, Auto Level, Auto Sat Dish, Stack W/D, King Sleep #, 17.5" Sailuns w/Disc, MORryde IS & Pin, Comfort Ride Hitch, 5.5 Onan, Res Fridge & Induction Cook Top