A military judge scheduled opening arguments for Nov. 6 in the court-martial of Pfc. Robert R. Garwood, delayed for months by motions and technicalities. Garwood is the only American serviceman to be charged with desertion and collaboration with the enemy during the Vietnam war and could face life imprisonment if convicted. The case took a new turn when the defense asked that prosecutors be required to divulge any information they have on two former marines who reportedly took combat roles against US forces in Vietnam, but are now living under government- provided false identities. The judge denied the request, saying he will reconsider it if the lawyers can document the accuracy of their source.