Yes, there are three agreed-upon mass ratios for Gold Filled: 1/5, 1/10, and 1/20, with a minimum karat of 10K. Ratios above 1/20 are considered Rolled Gold Plate (R.G.P) or Heavy Gold Plate (HGE) with karat ranging from 10K to 18K. It's worth noting that 9K pieces are not officially recognized as Gold Filled but are commonly found.