I will say that G2 has a nice gun there for sure.
BUT,, to answer the OP's question,, YES,, you can do a bit of MINOR custom work to use a NM Bisley g/f under an OM Blackhawk.
The screw hole pattern is identical, so it will screw right on. However,, the trigger return spring is different in the OM vs the NM. To use the OM action, you have to add a custom made insert piece to the Bisley g/f for the OM trigger return spring.
The little custom piece is EASILY fabricated, by hand out of brass, aluminum, or even steel.
To explain;
There is a slot in the NM g/f's that the music wire trigger return spring lays in. In an OM, there is a hole in the g/f behind the trigger for the coil trigger return spring & plunger. The little custom adapter piece is cut to fit the slot, drilled to accept the coil spring & plunger, and cross drilled with a pin hole to hold it in place.
I've made several out of aluminum, and it's NOT hard. I'll see if I can add some pictures.
