I'm pretty sure that it doesn't. I mastered the Sol Blade once, and then went back and got the Gaia blade because I forgot to grab it. I still had to master the Gaia Blade. I don't think the developers put too much thought into the weapon mastery system. I also don't see how it would be helpful, as the game gives you no reason to go back and master previous weapons.
Wait, lol, never mind. I wouldn't have been able to get it anyway. My memory is faulty. Curse you finals week!