@ The the real Mr I. If you applied your test to every topic of discussion I am sure you would say very little or be very boring to your friends due to your need to discuss only matter of great importance.
@ the OP. Yes it is weird to buy a random medal but you are making a bit of an adventure around it. If I were you I would start tracking down the medals of other long forgotten races and then make a series of it. Or maybe (going in a different direction) buy an early 90's london marathon medal and run the original route dressed in a shell suit / acid happy face tshirt.
Let us know how it goes. It could even be one of the few running blogs that would be interesting.