Yup, most main dealers over here have such a system.
What crap. That makes the very broad assumption that manufacturers only ever make and apply subtle changes to the design of their cars (be it internal or external, cosmetic or mechanical) on New Year's Eve. I don't think they do. Therefore there could be several small changes in the one year. It's a crap way of doing things. The only real way is to have a database that's linked to VIN no (and often reg no, though with private plates that can have its problems), in order to find the correct part. Other than that, it's just major model changes (referred to by Mk1/2/3 etc, or by manufacturers' own systems i.e. W126 etc for Merc and E32/34/36 etc etc for BMW).
Have you not got it into your head that we don't call it "model year" because it's too vague. We refer to different models by specific model designators (as I said above) - e.g. BMW 5 series goes E28/E34/E39/E60(?), with possibly one or two before that (google for john burns bmw for a good site with all that stuff on). That, and major facelifts within a model are generally referred to as that.
Because we don't refer to it by year. Get over it.
Most people would call it a facelift Mk3. It's how we do things. We use actual words such as adjectives and known descriptors to describe things.