I've seen low-rent repair shops snap a stud, then mix in a right hand stud among lefts because they couldn't find the correct one. Now you play roulette taking off a wheel. :scratch:
This might not be what you want to hear, but get those bastards off.... make `em all right hand. If you plan ahead to do it, it's not that bad a job. Definitely a dirty, tiring job, but not out of reach for the backyard wrench.