Dave,

Look through the rules for the classic racing class and determine if they specifically word the rules as model year or manufacture date. Some org's actually base it on manufacture date while others on model year.

if it's model year, then your SOL for an F3 HRC kitted NSR250 (Stephen and Andy have already pointed out HRC only supplied F3 kits for the MC16 and on which means model year 1987 and on).