Typically, GameFreak only gives the pre-evolutions of a Pokemon a different typing if there is a significant difference. For instance, Surskit picks up another typing as it loses the wings and gains a new means of transportation, while Trapinch and Swablu have nothing obviously draconian about them. I can't see a large enough difference in the designs to warrant a type-change. The only real reason to change it would be for the sake of changing it.
Back. Back in full May 15th. Please don't issue new gym challenges until that point.