Are we talking about the board or the cartridge because those are separate things. Many companies like SNK and Capcom sell a common motherboard with the game stored separately. Typically the boards conform to the JAMMA standard which is a single card edge connector that does coin, 1p/2p, joysticks, a certain number of buttons, sound and video.
The game is usually a cartridge with a separate small part that functions as a decoder or a license so to speak.