We all know the old children's song, "first the worst, second the best, thirdst the worst... too?" That was a quick way to realize that this is way off. Here's what I wonder when you look at a screw up like this - who screwed it up? Did the person who ordered the medal ask for 3rd and then the maker of the medal gave him 3rst? Or did the person who ordered it ask for 3rst and the medal maker just went with it? If someone orders something from you, like a medal, a sign, or a cake, and they give you messed up wording, don't assume that they know better than you. They will thank you for calling and asking, "are you sure about this whole 3rst thing?" They'll thank you for it.
You'd think that the medal maker would have some templates for 3rd place medals. Maybe he made too many of the wrong type and is now selling them at a discount. Hell, at discount prices I'll buy a 3rst medal.