That is right and would be printed in newspapers.
Microfiche anyone?
Good Call!
And if he did legally change his name, it would likely have been in Chicago, so that is where to look for old records of a name change.
My DH changed his name - had an unpronounceable and unspellable Eastern European name, he’s a naturalized citizen - and we discovered there are two methods (or were in the early 90s), one with a court thing (sorry I’m dumb about the correct terminology) and one just notifying the local newspaper a certain number of times. We did it the second way because it was cheaper.