Correction: they all fit well enough for the people working there. They all want you to go away for asking for a part they don't have. I don't know about where you live, but the people working in auto parts stores around here would loose a game of checkers to a screwdriver.

I'm sorry, I don't have the specs you need to buy an aftermarket replacement, but I promise you the actual part is under $3 from any Honda or Acura dealership. If you go to Acura, ask for the crank woodruff key for an 86-89 Integra. It should be the same.