As a matter of fact, Verizon does label the Galaxy S3 as a Global Ready phone. It says so right on the Samsung Lineup with the Globe logo as well as in the specs on the product page.
Network
LTE, CDMA/PCS/1xEVDO Rev. A (800/1900 MHz)
Global: GPRS/EDGE/GSM (850/900/1800/1900); HSPA/UMTS (2100)