Typically arcade machines have a lift out and pull system.
There is a small amount of vertical play, which allows you to lift the glass up a few mm. You then pull it out past the bottom
edge, and slide it back downwards.
The monitor glass itself was held in place by the top edge, as well as the control panel, when its closed.
A select few games used a set of screw-down bezel wood blocks.
Marquee's are usually held down with small strips of plastic, metal, or plastic and metal. Many have a channel to slide within, so only
need to remove one of the strips to get it out.
I suggest using Plexiglass instead of Lexan. Lexan may be easier to cut for control panels.. but its softer and scratches much easier than
plexi. Plexi isnt that difficult to cut in general squared shapes, polished and cleans well, and is pretty resistant to scratches. You can also get smoked plexi, to help diffuse glare problems.
Glass would be nice, but you wouldnt want to use plate glass. Thats a bit dangerous... because it could break and cut someone very
badly. Tempered glass is what you would want.. but you cant cut it. It has to be made to the exact size you require. If tempered glass shatters, it does so in a pieces which are small and are dull rather than razorblade sharp.