PAL or NTSC-J would suffice based on that logic either for the game or the lightgun.
I've understood that code added to all lightgun type games in North America to disable original Euro/Japan lightgun capability. However, there are still lightguns for North America, meaning a lightgun can be used with those few games, just not the original official Sega one.
Again, this is really to get feedback on a lightgun I can't see myself spending $70 on if it doesn't even work properly.