I haves 99 LS...3.1.
My son did the brakes all the way around including new hubs on the back.
He stripped a bolt on the front drivers side and now it feels like a warped rotor.
Two questions.
Can I just replace the bolt without pulling the hub?
Would one missing lug nut create this problem?
It drove fine before the brake job.

 

Probably easier changing the stud with the rotor off so when you pull the new stud thru the hub ( flat washer's and a lug nut ) you don't danged the rotor. Yes a wheel with four lug's can create a wobble especially if they are not torqued to specs.

 

Can I just replace the bolt without pulling the hub? Yes
Would one missing lug nut create this problem? Yes
It drove fine before the brake job they usually do

I had some new tires put on once and the tire shop broke a stud and they sent me to the Chevy dealer to fix it. They did it while it was on the car. they had a tool to do the repair, then pounded it out with a Punch.
Should be a sticker on the inside door frame that gives specs for torque on the lug nuts, 100 ft. Lbs. is most likely what it could be. You will need a torque wrench to do that.
You will need to either replace the rotor or have it turned if it's warped.
They can do that while it is on the car, the NAPA store here does that work. So you might check around. Anytime you over torque the lugs you stand the chance of warping the rotors. Or if you ride the brakes too.