b20b engine numbers, and clutch help!!

i was wondering if anyone knew the numbers on the b20b blocks, i have a b20 vtec swap, and the guy told me it was a 97 engine, so i was wondering if there was a way i could verify it by serial number..... also i am trying to buy a pressure plate and clutch for it, but everywhere i go says 97 doesnt have it or they cant order anything in for it? only 98 and up. does anyone know why this would be?!
thanks