I recently purchased one on Ebay, and installed it 28, July 17. The "Battery Life app reports it as 1751mAh capacity, stock is 1810mAh. I then fully charged it, then discharged it to ~ 55% and recharged using a usb dongle that calculates the mAh used during the charge cycle, that number was 1045mah and includes the power used to operate the phone. Calculating the maximum power based on that number it is impossible for the battery to have more capacity than ~2300mAh yet the label claims 2850mAh.
did the same test on my iPhone 6 Plus with original battery @ 93% capacity (2700mAh). discharged to 50% (1350mAh) external dongle says it took 1600mAh to recharge (including operating power during that time). If I assume 1350mAh is the portion of the 1600mAh consumed to charge this phone and the balance was operating power I would end up with a .84 correction factor, applying this to the ~2300mAh from the gold battery test would correct it to 1932mAh (close to the 1750mAh reported by battery test). I could do a more detailed and controlled test and narrow the results further but I think this is enough to prove the 2850mAh claim on the gold IPhone battery I purchased is a scam.