I don't think so. I had the same with my 335d. It turned 3 just before the end of the AUC period, so I asked if there was any difference in cover / cost between extending the manufacturers warranty and the AUC.
I was under the impression that they have slightly different levels of cover. i.e. trim is included in the manufacturers and not in AUC. So you would be pretty peeved off if you lost that cover and something was needed within the first 3 years of the cars life.
In other news, my mechanic screwed up with my service today. The 330i went in for a service as I've only had it for a week. So it went in for the full service. He said to me £130. Bargain. Turns out the parts bill was £126 for the service. Ooops. He'll get a nice christmas tip though.