note guys that there are two versions of the m22 bookshelf for "wall" mounting. The older style that has a good portion situated on the wall itself (the w22's) and the m22 in-walls (yes - same name as the bookshelf for some weird reason) that comes out only 5/8 inch - but has a much larger cabinet in the wall cavity.
As I understand it, OP has the 5/8 inch verion - the whole design is based on being 5/8 away form the wall surface. It's not about cosmetics or mounting - it's the acoustic design - so I would not mess with it.
