You are wasting your time and money buying a bezel for a TV if you aren't going to decase it (which is VERY easy, I have done lots of them). A Happ bezel will fit a traditional TV tube perfectly if it is decased, it won't look right if you don't decase the sucker. The idea is that the bezel sits right on the tube and provides a clean look, if you don't decase then it will be floating an inch over the tube, thus negating the whole idea of a bezel in the first place.
Decasing a TV set is quite easy to do, don't let a 10 minutes of work and a single piece of wood from the hardware store stop you from having an awesome machine.
Decased TVs are also more functional for emulation use, because they don't have the heat problems associated with putting a cased TV in a cabinet AND you will have access to all the normally hidden adjustment knobs on the chassis. Fine tuning those can often make your TV-out picture look a lot better (you can fine tune the height and width and focus and all that).