That sounds like a 126 mm spaced (6) 56 cm (56) road or touring frame, the 28th (0028) produced in November of 1989 (1189). That late in the year would make it a 1990 model. All Cannondales were painted at that time, but someone may have stripped the paint. Download the 1990 catalog and see if you can match it to one of bikes listed.