I was wrong, it's not the "new family" but the "Improved Family" (or IF) that is the early 15 model. This is probably a 15-30 or it's a 115 (they are identical on the top side). If it takes a class 15 bobbin it's a 15-30. The earliest IF machines do not take a class 15 bobbin, it's a bit smaller. Singer used this decal pattern from 1900-1930.