It just looked a lot like the last 1921 butt set I had in this old pic below. I thought it might be a 21 as even the numbers looked close and in the 21 range. http://www.fototime.com/0480573F66DA22A/standard.jpg
http://www.fototime.com/1AF8483184A4FCA/standard.jpgI had 1921 before with the numbers stamped but no longer have it to compare to this one. Thanks http://www.fototime.com/756019160AED0E5/standard.jpg