craig,
it is not dangerous (nor uncommon) to have the tires overhanging the wheels on a cushion-tired truck. the tire size on your capacity plate is the tire size you go with. Yes the tires overhang your rim but they do not mechanically interfere and they are the size called for on the cap plate. by your description they were overhung on the correct side of the rim. Enjoy your new tires.
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