My Grandmothers Sewing Machine

Cannot find a name on it anywhere, I assume its worn off. Did find a number under the front slide plate (which is missing): 1866872, also notice above this number is a 1. It seems to be a National Sewing Machine. I have seen a "Brunswick" which is similar with the same decal, but did not have the same Inspection plate. Any help with ID would be appreciated and where I may find some parts, treadle belt, front slide plate, bobbins.