OEM Xenon Retrofit onto a car that used to have Xenons

Alright this a an odd situation; So after I bought my car I went and looked up with BMW VIN decoder what the car had from the factory. Well, The car was equipped with Xenons from the factory, but the PO seems to have replaced them with halogens. Now my question(s): Can I buy any Pre-Facelift OEM Xenon headlights used from somewhere(ie. CL, eBay) and just plug them in? Will my car have to coded, and can I do it with PA Soft? Also what has to be included with the headlight to make this work? My car is a 2001 330ci. Thanks in advance!