The weapon HUD sprites that use the buster are translated from the Mega Buster HUD. That's nice, but lots of weapons aren't busters, but instead hands, for example Slash Claw, Charge Kick, and Junk Shield. It would be nice to have base hand positions with the Mega Buster palette for easier modding.
The Mega Buster palette is not needed for sprites like the Metal Blade and Hyper Bomb ready sprites or most of Hard Knuckle, where the HUD couldn't conceivably be used by any other weapon.
Also, speaking of Metal Blade...
The Metal Blade HUD has artifacts just below the crosshair.
EDIT: Maybe you could put some comments into the TEXTURES.HUD file to explain which hand position has which name.