90 vintage EG had light grey zolatone paint, white lettering and cantis, 91 dark grey zolatone with orangey red lettering and you guessed it cantis.
U brakes were the 'in thing' 88/9 I believe. Final year Uni housemate had a nice Kona Cindercone with U brake rear which puts it 88 (forgive vagueness I was a student at the time - bitd when students were proper students)
US models had different paint and spec across the years so dig around; Marin anoraks will be able to decode the serial number to confirm vintage (I'm more of a Pace anorak these days)