Thanks for the reply.
The reason (I think) the balancer split on the Saturn is that there is a
rubber piece "sandwiched" between the inner and outer metal pulleys. I'm
guessing the rubber deteriorated with age, split, and caused the balancer to
fail. So that is why I am worried about getting a used balancer from a
junkyard. Without knowing the age of a replacement balancer I would get,
the rubber portion may already be in bad shape, especially if it sat around
exposed to weather for any amount of time.