Some add genuine top glass, though I suppose it could also be done with acrylic, though it'd need to be fairly thick and probably cost the same as glass.
With regards to the backglass rea, some do it with a vertically-mounted wdescreen and just set up windows in the correct location for the artwork and dot matrix display, whilst others use a dual graphics card setup with 3 monitors (usually 46" WS playfield, 28 or 32" WS backglass and 15" 4:3 dot matrix).