According to the teardown, the Epic 4g uses the multifunction Qualcomm QSC6085 for GPS functions. (Presumably this is because of the CDMA radio, so the Fascinate design is probably similar.) Previous analysis the GSM variants, based on the international I9000 model as well as the Captivate and the Vibrant, showed they use a Broadcom BCM4751 chip.
This would explain why the symptoms of the GPS problems on the Epic, and the firmware modules, are not the same as those on the GSM variants. But amazingly, it seems that Samsung managed to screw up two different GPS designs in two different ways.