Candy cabinets seem to be almost completed standardized when it comes to control panels. Every one that I have ever seen has two joysticks (usually Sanwa brand) and either 4 buttons or 7 buttons. The models that have 4 buttons will always have 3 plugged up button holes, which can be filled with the extra buttons to play the Capcom fighters, like Street Fighter 2. The ones with the 4 button layouts were often equipped with NeoGeo MVS hardware.