I don't think it fits gunbreaker at all. Blazefire/blaze-edge saber functions as gun-blade it has 2 modes, so it's either a blade at one point or a gun never both. A gunbreaker's gunblade which took from FF8 is a blade with a part of the gun to pull to make it vibrate and hit harder, gunblade. Also, ff8 gunblades does not transform so what you see is what you get.

But if they do give us i won't say no to more glamours.