--Never say never.  For a burial in a VA cemetery, the religious symbol that appears on the headstone is up to the deceased's family and if the family was not Jewish, say the veteran converted, and wants a cross on the headstone, that is what goes on it.  The only exception I am aware of is headstones of US veterans buried in US Military cemeteries overseas for whom Operation Benjamin was able to instigate a change from a cross to a Star of David, but even then a family member must agree to changing the religious symbol on the stone.  
Herschel Sheiness
San Antonio, Tx
jsheines@...