anyone who ever made SW for autorespone programmer knows that only few % of GW cards have ID placed by manfacturer in MCU , and that about 10% got ID 0560 , iD for pic16f877 is quite different and cant be mixed if is programming SW corectly maded . That custom ask is this, every microchip (but also other manfacturer) MCU got space for custom ID and other data stored in "spetial" pocket of flash.Having no manf. ID in GW is proably your problem about correct identifikation GW card, but that is mistake by developer of programmer you use.
regards