Hi Paul, I can think of two possibilities...
First, you can put an Alpina sticker on anything and most people won't question it, just look at all the fake Alpina steering wheels and such on ebay.
Second, could they be Borrani wheels? These were sold by Alpina, but I wouldn't have described them as solid - they look more like steel wheels without a hubcap. I've never seen 5 lug versions, but they're a favorite of the 02 crowd. So, if this guy isn't too familiar with coupes, is it possible that he actually saw a 2002 with Borranis?