If the coin flip is to determine who gets the medal and who is the "winner," then the winner of the flip WINS THE MEDAL, HE DOES NOT WIN THE MATCH.
Awarding third place points where no match can be wrestled is, as has been pointed out, a clear violation of the rules. Therefore, if no coin flip is utilized, both wrestlers would receive third place medals and their teams' fourth place points. This would be a legal solution.
Using criterion to "break the tie" so as to award third place points would be a violation of the rule.
Also, in thinking about Mr. Kuhn's soltuion, could this not lead to an illegal match being wrestled? I say this from the stand point that the time left in a wrestler's day COULD be less than that of a legal match; or, he may run out of minutes in the 3-4 match if he had had to wrestle multiple overtime matches in the day. Not likely, but possible.