Wiesel is exactly right on how the pulley is constructed. Like I said, there is no way the retaining bolt would come loose, unless someone had it off previously and didn't properly re-torque it. And, yes, it is a press fit (requires a puller to remove), but there is no keyway....except on the aftermarket UD pulley that I have on mine.
The stock pulley has 3 "spokes" that you can get a pry bar through and wedge against something on the engine. This will allow a re-torque. The SLP UD pulleys I have on both my Hemi's don't have any spokes and a strap wrench must be used to stop the engine from turning over when torquing. IIRC, the torque is ~125 ft. lbs. That's why I say it'll never come loose, unless someone has messed with it before and didn't re-torque.
06 GCO, Dk Khaki, QDII, Flshing Hi 3rd Bk Lt, MDS "ON" Lt, Airtab Vortex Gens, Debadged, Fumoto Drain Valve, BT Catch Can, Chopped EGR Tube, SRT8 CAI, K&N Filter, Sonnax Trans Line Press Booster, SC Tuner W/Adv Trans Tune App, DS Tuner, Cust tubular hdrs w/3 in Magnaflow/Xlerator AP Exh Sys, Bilsteins, SRT Springs/Sways, Cust Eng Cvr, SRT8 frt/rear bumpers, FRI Sidewinder Cam/6.1 valvetrain, SLP 25% UD Pulley, BBK true 90mm T-Body, SOS Ign Coils w/.060 spark plug gaps, SRT Reps with 265/45&295/40X20's.