UK Stocks-Factors to watch on June 20

June 20 (Reuters) - Britain's FTSE 100 index is seen opening 15 points higher at 7,619 on Wednesday, according to financial bookmakers. * BAE SYSTEMS: The U.S. Marine Corps has awarded BAE Systems PLC a contract for wheeled amphibious combat vehicles (ACV) that transport Marines from ship to shore under hostile conditions, the defense contractor said on Tuesday. * BHP BILLITON: BHP said on Tuesday it has agreed to sell the Cerro Colorado copper mine in Chile to Australian pr