1987 IBM Model M Keyboard: Membrane Replacement (+ Bolt Mod) 

Hey man. I did the same thing with my bolt mod. Didn't put the silicone sheet between the flippers and membrane sheets. My Model M did feel sharper in key presses, and decided to leave it in for a month or so. However, the idea of wearing out the pads got to me, and ended up taking it all apart and putting the layers in the right order, with the silicone layer behind the slippers. There is a noticeable difference, but the longevity is key. Probably why the layer order is the way it is.