This is Radiant Silvergun, as taken from the interwebz:
The first thing that hits the eye is the custom in the bottom right not being sanded, but rather proudly marked; including a specific sega part number.
The two GALs on the bottom center, replaced on yours with two 74LS373 TTL ics, are also imprinted with a sega part number.
Note also how Sega had branded mask ROMs. On your picture the Macronix 29F16 flash memories are manually numbered with a pencil.
And let's not forget the number of layers!! As the expert eye can see on the original Sega board, the PCB is definitely 4 or more layers. Your cart, on the other hand, has very likely just two. Due to this, the power distribution strategy on the board is entirely different. Finally, the font used on your board to apply the PCB part number is different than the stroke font used for everything else. This might mean that it has been added at the last minute before rendering the gerber files. on Radiant Silvergun instead the same stroke font is used. And by the way, the only sega part number that can be seen around is the PCB model.
Although I don't own any ST-V game, I would still definitely consider the board you posted as a bootleg.
My 15kHz cabinet Peplos will never power up, with any item, and I am quite proud of that.