If they didn't cut wires underneath it can be replaced. Take the ignition out, if the wires aren't connected to a wiring harness mark the wires, on mine the wiring on back of the ignition on part of the plug that can be detached.
Take the ignition to a lock smith and they should be able to install a new on with a key.
2002 Monaco Windsor 38 PKD Cummins ISC 350 8.3L
2005 Jeep Grand Cherokee w/5.7 Hemi