I'm almost certain he'll take the rematch. Not only will he want the belt back but each fight in a trilogy always make more money with each fight. There's just more buzz and interest.
I'm sure there'll be interest and no doubt a boatload of money to be made but I can't see the interest being at a similar level. A third fight pops when the previous two left the questions unanswered.
Both this and Ruiz answered the question in the second event. In terms of actual narrative a third one would be pretty redundant.