Your memory is good, but tighten up your wheel bearing play and try the up and down motion again. Your wheel alignment guy could've mistaken loose wheel bearings for bad kingpins. Could be a simple bearing adjustment.
To check the side to side play, I would first roll down the drivers window, stand outside the truck, and gently move the steering wheel back and forth until resistance is felt, meanwhile look at the tire on the drivers side, it will be moving back and forth slightly as well. Two or three inches of free play in the steering wheel is normal for these beasts but if you have much more than that you'll need to investigate further. Have someone else do the steering wheel movement while you look under the truck with a good light, you should see all the steering parts moving in unison. My guess is that most of the play is in the steering box and can be adjusted out following the procedure in the shop manual.
