CREATE TABLE table_19901_1 (trigger_pack VARCHAR(255), rear_sight_type VARCHAR(255), colt_model_no VARCHAR(255))
What is the trigger pack on the Colt 602 with the a1 rear sight type? 
    
SQL: SELECT trigger_pack FROM table_19901_1 WHERE rear_sight_type = "A1" AND colt_model_no = "602"