He would make substantially more, specially with PPV points, having said that, i dont think he makes exactly peanuts this days tho, just needs to do a little more talking to sell his fights better.
Edit: I doubt Conor would try to fight him before getting the RDA fight, him losing to Lawler would kill his chances of a another title fight following that loss, he would be forced to defend the 145 belt, something that a few people already think he will not be defending it and its just riding it up to another title fight and the "2 weight champ" thing.