I think thats complete bull shit on the dealerships part. Go get a second opinion. I have never heard that claim before. Odds are the pull is from worn out tie rod ends, or your alignement is off. If the pull is only during braking then you have a sticking brake caliper. Its a 2004, not a 2013, so its not as advanced as they claim. My friend as an 04 320i and I did his power steering pump swap.
Also im hoping you got a PPI and did a VIN check before purchasing the car so you would know the history. Its not the end of the world if the car has been in a wreck, but its important to know ahead of time. Specially if bought from a dealer.