Nice find. What a hack job?! If you are very careful you could just use a cheap jamma connector or harness from eBay and let a little of the connector hang off as long as you pay attention to the alignment of the connector with the board. There's a lot of excessive unnecessary solder globbed up on the card edge, you should soak up as much of that as you can before fitting the new connector. You should also cover the exposed window on the ROM chip at U31. (!)