Slap Fight irregular/bootleg 2x22pin version - pinout?

[raiden]

I´ve bought this thing on ebay and can´t find a pinout on the net. The common Slap Fight version is Jamma, 2x28pin, but mine must be a bootleg or an early pre-Jamma version. It´s also NOT the Tiger Heli pinout, although several pages state both are the same hardware, on my PCB pins 3 and 4 are connected, while the Tiger Heli pinout has different voltages for pin 3 and pin 4.

Does anybody have an idea what the pinout is for this game? Actually, the auction called it Slap Fighter, but I haven´t found any info on such a game at all.