His subsequent reclassification to 4-F makes me think that the 1-Y was for legitimate medical reasons.
I looked it up earlier. In the 72-73 time frame when they ended the draft, they ended the 1-Y classification and moved everyone in 1-Y to 4-F. It seems if was a bureaucrat paper shuffling thing and the individual never even knew that happened.
The guy could have a hay fever problem of a case of psoriasis that the SS deemed 1-Y before and changed to 4-F without even looking at him again.
It does not mean he was not able to serve. It just means they didn't want to deal with accommodating that particular condition. In WWII, they were no where near as accommodating.
All 1-Y's became 4-F's in December of 1971 automatically. So just because one was reclassified to 4-F doesn't mean that one was legitimately classified originally as a 1-Y.
I would like to see the records of Trump's September 1968 physical exam to see if his October 1968 1-Y classification was legitimate.