I've uploaded another picture in this thread with a true yellow gold Breguet next to the 3137 and I can now see the difference. It's darker and I really like the color. It's so unique.
I'm also a fan of gray gold but I think yellow/rose gold pieces are so classic Breguet and they also look better on the wrist. I won't have this polished for sure, the color is really unique.
So I recently acquired a 3137 (presumably in yellow gold, but I'll go into this later) and a 3337 in rose gold. I then brought them to Breguet in Switzerland for servicing. After a couple of weeks, I received the estimates, and the one for the 3137 stated that it's a "3137BR". I replied, indicating