The state attorney general's office has won a court order allowing it to examine petition signatures gathered to put the anti-AIDS Proposition 64 on the Nov. 4 ballot. The order issued by Los Angeles Superior Court Judge Warren Deering is part of an investigation by the attorney general into whether some of about 500,000 signatures that qualified the measure for the ballot were illegally obtained. If passed, the measure would give acquired immune deficiency syndrome the legal status of an infectious disease and would attempt to bar victims and carriers of the AIDS antibody from jobs in restaurants, schools and medical facilities. It is backed by supporters of political extremist Lyndon LaRouche. The investigation is not likely to disqualify the measure, but it could result in criminal charges against anyone found to have engaged in misconduct while gathering signatures, officials said.