The receiver sight, I do not believe was ever intended for a 414 without drilling additional holes. I've never seen a sight that utilized the slot and single hole except the one made exclusive for same.
The tang sight shown is the Lyman 103 and will cost $300+ unless you are lucky, it is missing screw in disc (as Lyman called them at that time)

I think the sight in the picture you provided (Stevens No. 42) is not the one you need to look for.  The proper sight is much less sophisticated than that one and was only used on the 414 rifles.  It has an "L" shaped frame that sits in the slot in the side of the receiver, held in place by a single screw which also clamps the elevation indicator in place.  The sighting orifice is drilled into a flat, rectangular piece of metal that sits in a slot on the top of the frame and slides back and forth to provide windage.  It is held in place by another screw that fastens from the rear of the frame.

I don't have acces to a camera right now, so I can't show you the sights on my two 414 rifles, but here are a couple of links to firearms for sale that have pretty decent pictures.  You will note that the first one has a little sighting notch someone has filed into the top of it, but otherwise looks correct.  The second one is missing the elevation indicator.

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As an alternative if you are looking toward shooting the rifle, it should already be drilled and tapped for a Lyman tang sight, which can be had from several sources.  The Lyman No. 3 shown in the picture will be expensive and also hard to find, but a No. 1 or No. 2 should work fine for about 1/3 the cost.

Here's a link to the Lyman site.  You might contact them to see if they have what you want. :

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You might find an original on the gun auction sites.  Also, a number of places now offer reproduction sight discs.  I think Lyman and Marble discs have different threads, so they probably won't interchange.

Aperatures 'N' More has replacement aperatures for around $10. I have a Pacific reciever that fits the original holes in the reciever. Might be interested in sale or interesting trade. PM if interested. I took it off my 414 after I found the correct sight for mine.

One screw. It was on my 414 when I bought it many years ago. Replaced it with the correct factory sight when I finaly found one.

Have never actualy taken my own photos and posted them. Have done it with pictures off auction sights and from others. Have the camera. Will have to find the time to play with it and see if I can get decent photos. Sort of busy right now.