For sure you'll want to add shocks too. I wonder why somebody took the shocks off? Think they never had shocks on it? That would be odd.
'03 Freightliner FL112, 295" wheel base, with '03 United Specialties 26' living quarters, single screw, Cat C12 430 h/p 1650 torque, Eaton 10speed , 3.42 rear axle ratio