Ideally, SameBoy and bsnes would just be selectable as core in Config > Cores > GB, instead of having to go through the rigamarole of checking the GB in SGB menu item.

They could both have the suffix (SGB), to clearly indicate they're specific to SGB.

The only potential problem is Game Boy Color games that don't support Game Boy mode, but certain GBC games work in Super Game Boy anyway, so it's not a problem specific to this suggested UI improvement. If it really becomes an issue that needs addressing, it could be treated like QuickNES, where certain games are not supported (ideally, it would probably be detected and reported by the core if that's possible; a whitelist would be much less ideal).