Pat', that is interesting.Never seen one like that .
Beretta tried a similar type of trigger in the '70s (?) on some o/u guns, same kinda idea.I think the upper groove was for the top bbl n the the lower for the bottom, but It didn't seem to catch on.I have read Graham Greeners book a couple of times, but don't remember seeing anything like that .What kind of serial # range?
I bet someone here will probably know a bit about it..
cheers
franc