Quote Originally Posted by argus
I don't think that will be a problem as the grinded face of the glass must point towards the lens.
The only critical measurement - as you might already know - is that the grinded face is in exactly the same position as the film.

My ground glass is even a little bit thinner, only about 2mm.
1/8" = 3,175mm

Normally ground glass thickness is not criticle, unless you have a mount that requires the screen be slid into a slot, as long as the ground side of the screen is in the correct registration for the film plane, you should have no problems at all, the most important thing is to make sure the ground side of the glass is in the proper orientation of where the film in located in the holder.