Montanan.....
That's the Lyman #2 tang sight on my 336cb you see in the photo. If I remember correctly, I got it from Brownells, but it has been 5-6yrs so I might be mistaken.
Anyway, I believe the Midway and Brownells Lyman tang sights are identical. I'm sure the pic you posted of the Brownells Lyman tang sight is the Winchester version with a longer base.....that's probably what's got you thinking there is a difference. If you know something I don't know, please correct me.
One thing about it, the Lyman is a good tang sight. There are those who won't think of it....and prefer the Marbles because of its windage adjustment. The truth of the matter is, once the front sight is drifted into allignment, the Marbles no longer has any advantage over the Lyman. I wouldn't blame anyone for getting the Marbles, but they are spending a lot of money to avoid a very simple drift of the front sight. I drifted mine in about 15 minutes at the range, and its never needed further adjustment.
hog