The repair should be short, only about 20-30mins tops, to swap them out. If it has to be pinpointed, maybe a little longer.
They should be able to check it with a lift, spinning each one freely to see which. If not, take it on a test drive to play it out for them.
In my case, they couldn't tell (or refused to verify) it on a lift, but I insisted they drive it, once it was 25MPH+, you can clearly hear it howling and they changed it, took 20mins.