Johhny Got His Gun may be a special case, since it was virually unreleased until 1959, but, yeah, "Steppenwolf" is definately a book that resonated with the 60s.
Indeed, those two books may be special cases -- books written long prior that resonated so exquisitely with the period that it is the 60s with which they are identified.
[btw, from what I'ver read online, JGHG was 'withdrawn' from circulation, with Trumbo's nod, because of the war. I don't think it was banned in any legal sense. I gather from what I've read that it was delayed in getting back in circulation after WWII because of Trumbo's HUAC problems -- but, then, maybe it was the Korean War.]