Mitt still isn't pro-gun. He still supports the assault-weapons ban, or at least he did in May.
I bet it would be revealing.
I was looking at a Massachusetts gun rights organization, GOAL, and there was an article there that pointed out that the number of licensed and registered gun owners went down while Mitt was Governor (25%? Something like that), and another article that said that Massachusetts had built several “bonded gun warehouses” to store confiscated firearms, pending destruction while the owners litigated their cases.
Mitt, NRA life member and lifelong hunter, signed a bill that required, in no uncertain terms, that the gun owner got a receipt for the confiscated guns (shades of “Brazil”!)