Howard,
You have good questions, and although I am not sure I can provide valid answers, they deserve to be addressed. So, if the rest of the forum can put up with a little more "Luger forensics", lets give it a shot.
To begin with, I think that most of the questions so far have been generated because this sight was refinished, rather than restored, by a non-professional who either did not have knowledge of the proper configuration of the sight, or was not concerned with preservation so much as improving the appearance and making it functional. I would venture to guess that the sight was in pretty sad shape when he started, as many Navy Lugers are from the salt air and water exposure. The "cosmetic" refurbishment produced the flaws noted:
1. As Dwight pointed out, the top edge of the sight itself is the wrong contour.
2. Also as Dwight pointed out, there are finishing marks on the top surface of the toggle knobs, and the toggle flat just behind them.
3. As you have noted, the leading edge of the sight is not flush with the body of the sight where the 100 is marked.
4. As already discussed, the rear of the sight has been ground away and made flush with the body.
I believe that the heavy grinding on the rear of the sight was not done to remove a relatively shallow serial number, but to remove pits and smooth up the metal. Not knowing that the sliding portion of the sight should not be flush with the base, the refinisher carefully ground them to bring them into alignment or it was necessary to grind it that far to remove pitting/damage.
This is not the only thing that was done that "does not make sense" as you observed. The very beginning observation by Jerry Burney that the "200 should be in the white" points out that the refinisher was not familiar with this characteristic or was not concerned with a proper restoration.
The leading edge of the sight not being flush with the body I believe is once again the result of the need to remove excessive amounts of metal to eliminate pitting or blemishes. As you originally noted, the numbers are poorly executed, particularly the 100. If you look at the placement of the 100 as well as the alignment of the surfaces of the eBay sight vs. an original, it is clear to see that the eBay sight has been ground down and renumbered.
With regard to your sight having a finer checkered pattern than the eBay sight, it may be finer, but I think that it could be an illusion caused by the photograph and the fact that the â??pointsâ? of the checkering on the eBay sight have been worn down and therefore appear coarser. If you count the actual number of lines on the button I think you will find them to be very close to the same number as on your SN 29 sight.
Hope this has been of some use,
Ron