www.klov.com If the game that wa in it is jamma, the cabinet is jamma

Joust was not. But if this was a conversion cabinet that doesn;t mean the cabinet isn;t jamma. Some coverter could have taken place.
BTW, if it is or isn;t jamma, like I said, it can be converted easily. JAMMA is just a wiring standard. It's that harness that plugs into the game. Standard pinout. Old games won;t be JAMMA but can easily be converted since it's the same hardware, just wires need to be wired to the jamma edge connector.