NOTE: Paul Kirk Jr. - This is Fentec, but it's a much later issue. There is a creamer in this shape to match. I suspect this is an open sugar. I've had this shape marked with the later McK in circle, not used until the 1930s. And it appears regularly in milk glass, too, another indication of late production.
NOTE: Many of the reissue pieces have a smooth edge as original pieces have a small toothed edge. Jeannette Glass Co. acquired many original molds.