Can't tell from the picture, and probably would not be able to tell with a better picture (at least not me - maybe someone else could).
Odds are it's either a Williams or a Lyman. I've heard the inserts are interchageable for those two, but don't know that for a fact. You might go the the MidwayUSA website and look at the pictures of the globe sights and see if you can match them up.