I have three double trigger Superosed Brownings. Only one is a single/double trigger. I can not tell if the other two were at one time. I have read that Browning converted every one to regular double triggers if they were returned for service. No part available and a regular double trigger can be about the most reliable trigger system there is. My two regular double triggers have been faultless for 30 years. The single/double does give me a bit of trouble but nothing a little blowing out with air and making sure the stick is not an interference has not fixed.
I have been thinking about buying a couple of the FN double trigger guns made for the European market. But every time I find a nice one it sells for twice the high estimate. So many nice guns and so little time and money. All the FN double triggeredguns seem to be a normal double trigger setup. I don’t think Browning ever worked out all the bugs in their new design and everybody was moving to a single triggers so it just died a natural death.