Well, I guess it WAS good exposure... someone found you from it 30 years later. :) But seriously, you say you don't remember signing a contract, and contracts go both ways. If it's your byline and the publisher (your old prof) never secured rights, you technically have
some rights to the piece. However, with the situation as you describe it, and since you are able to contact the publisher, I would go ahead and do that if you chose to attempt to resell the piece.
The far, far larger concern for me would be to contact the potential buyer and find out what he/she has in mind before you waste any more thought on this or go through contacting the prof. The phrase "a small kindle project" has so many red flags to me. On the far end, someone may be trying to do a rights grab for the piece which they will then use in a much larger project (or even re-sell themselves), and on the less-malevolent-but-still-not-worth-your-time side, this could truly be a small kindle book and they have no expectation of giving any payment. So, step one is to find out exactly what their proposed use it. If you think it sounds like something you want to get wrapped up in, THEN contact the professor as a courtesy.
So, my steps would be: 1) Find out the full details of use, and what they want (maybe it's just a pull quote, who knows?) There is a huge difference between, for example, someone wanting full rights to your by-lined interview of Don DeLillo, and a guy writing a book about vacuum tubes who wants to use a one-line quote from your written up interview. 2) Go to the prof if you want to pursue this and ensure he agrees you have rights (it's the disagreement I would worry about... the front of the literary journal certainly says he is the copyright holder, and it would be up to you to prove your rights.). 3) If you do go ahead, get a contract that states that the kindle person only has use rights, not ownership or reprint rights, and only for the Kindle edition, etc. Really nail the contract to this very specific project if the claim is that what he/she wants it for.
If you have a lot of time on your hands, you could enjoy this piece about an attempted rights grab:
http://thecoachellareview.com/fiction/thepayoffwillbeingoodkarma_stevealmond.html