Ah, not exactly. There are bearings that must be precisely adjusted. What kind of headset are we talking about here? If it's the older-style "quill" type, you'll most likely need a special headset wrench in addition to a large crescent wrench for the locknut/cap.
If it's an "aheadset" type, you can do the entire job with the proper allen wrench, but again you have to adjust the bearings properly.
Headsets and steerer tubes are pretty tough; I'd be inclined to just do an inspection. Remove the front wheel and see if the fork rotates smoothly through its range of motion, with no little catches or bumps which might indicate a split bearing or a dented race. Put the wheel back on and apply the front brake while trying to push the bike back and forth. You should be able to feel if there's any play in the headset.