The rules for doctors and dentists were not the same. My dentist was drafted into the Air Force in that era, he’s told me about it. He was stationed at Gitmo, which at that time he said was paradise. Incredible snorkling, fantastic sea food. (No Islamic terrorists.)
So, I doubt he’s lying.
During their senior year of medical school, physicians could indicate a preference for one of three options: The first option allowed a doctor to join the military service of choice immediately after internship. The second option allowed a physician to take one year of residency after internship, then discharge his military obligation, and subsequently return to a residency. The final option allowed a doctor to complete residency training in a specialty of his choice before fulfilling his military obligation. An individual based his choice on his own assessment of the future with respect to the need for military physicians and on personal considerations. Stating one's preference, however, brought no guarantee that it would be honored. Assignments were given at random, and many physicians who sought deferment for residency training were instead slated to fulfill their Selective Service obligation immediately following their internship.
So in other words he was not drafted.