This is true. When I was in Chicago last weekend I ordered a "Kalamazoo Wheat" and the waitress asked the bartender for an Oberon. I asked "like WTF?" and she was all like "they have to sell it under a different name, but it's Bell's."
Place was Mack's (IIRC) in or around Wicker Park. I think. Near Damen and Division, anyway.