mware, those may be quite valuable. In those days, there weren’t that many students at Princeton, plus during the 30’s some would have not purchased yearbooks due to finances.
I would be surprised if more than 5,000 had been published in any given year, and most of those are probably not in existence any more (fire, flood, people throwing them away, etc.).
Given that it also has celebrity and historical value, you should hang onto those unless you decide you want to sell them.
Vanderbilt's, included. Some of the professors are also pretty famous, especially the physics dept.