She is the Gotz forerunner for American Girl dolls--possibly the sculpt that Pleasant Rowland discovered in a storeroom at Marshall Field's in 1985 and decided she was going to talk business with the manufacturer.  A closer look shows you she is 100% made of vinyl, and therefore not Pleasant Company or American Girl.

These early, vinyl Samantha Parkington look-alikes can sometimes be found on eBay, though almost always they need to be restrung and a number of them seem to have a pinched torso from extended time on a doll stand.

If the face has a mold number, I'm not aware what it is; the neck only reads "Gotz Puppe." But back in the 1980s, Gotz's name for one of the associated dolls was "Romina" before the sculpt was purchased by Pleasant Rowland for her fledgling business The Pleasant Company (later American Girl).  I've heard this face referred to as the American Girl prototype, so that's what I call it (though it's not actually, if you want to get technical).

These dolls commonly come in both girl and boy varieties. I've seen about an equal number of each make the rounds on eBay. I've also seen one or two blonds or gingers, but most of them are brown-eyed brunettes, just like American Girl Samantha, whose was based on the vintage Gotz dolls.

There are minor differences between this sculpt and the Pleasant Company/ American Girl sculpts. For example, Pleasant Company dolls have larger teeth, but they are overall nearly identical. However, the smaller, thinner vinyl torso of the Gotz dolls is what mainly differentiates most of them from their Pleasant Company successors.