Throughout the mini-series, Robert, while serving as Attorney General, is addressed verbally as "General". Although Attorneys General are addressed as General, this is done only when they appear or are referred to in either a U.S. Federal Court or the U.S. Supreme Court. Outside of these courts, protocol dictates that the AG is addressed as either "Attorney General" or "Mr. Attorney General".
When "Dr. Feelgood" is injecting Jackie Kennedy the camera shows him withdrawing the needle. As the needle exits her skin, you can see it is a flat spring loaded "Special effects" needle and not a real hypodermic needle.