If you were drafted into WWII or Vietnam, did the armed forces take into account your desires or skill set when deciding where to place you, or was it completely by chance?

by Ekooing

Say you were any engineer before you were drafted into the Army? Would they take that into account when deciding what your job would be during the war, or was it just as likely that you would be placed as a GI? Or if you had a strong desire to be an AA gunner in the Navy and maybe some skill set that would tend to make that a good position for you, would that be taken into account, or would it just be the luck of the draw whether you were given that job or the job of being a cook?

Also, for jobs that required special skill sets (engineers, pilots, etc), did the military take draftees with any background and train them, or were those positions only filled by men who enlisted and happened to have the required skills. My grandfather was a B-17 pilot who enlisted before he got drafted. He said the reason he enlisted was because he knew he wanted to be a pilot, and if he got drafted, he would have probably ended up doing something he didn't want to be doing. But if he had waited to be drafted, was there any chance he would have been placed as a pilot (since he obviously had the skill and desire to do so), or would he have been given a random position?

Georgy_K_Zhukov