I don't have a definitive answer on this -- I know how long employers have to keep their records for purposes of providing them to the government, but I've never seen where they're required to provide them to the employees. Thinking of the corporations I've worked in along the way, I don't think anything short of a court order would have turned that information loose to me.
If the employee wants to keep up with their income (not a bad idea, really), they should be copying the timecard before turning it in, and copying the check before cashing.

