Stearing rack leak on 300C

I just had my 2006 300C into the dealer for a brake job (41K Miles, 4 years old). They told me that I have a leak in the steering rack. I don't have any symptoms, the steering has been fine. They've ordered a new rack for me, the plan is to replace it next week. I was wondering if I'm being taken. Is it common for a 300C to have this kind of problem at 41K miles? Why do I need a whole new rack for a leak, aren't there some seals that can be replaced? BTW part of this is being covered by my extended warranty (GE not Chrysler). The warranty only covers crap parts, the warranty company will pay for a rebuilt, I have to pay the difference to get a new Chrysler part.