Are the strings original?
Dave, It's my educated guess most of them are, other than those that obviously aren't. looking at the oversize bridge pins, it looks as though a plain core wire would go between them with barely any offset as you can see by the "replacement" wire.
The instrument looks to have been built to accept this idea. The bridge pins look as though they are smaller further up the bridge.
The Érard I saw with the covering on the strings in exactly this fashion had the usual 4-5 metal struts in the form of a rudimentary plate so, while I didn't check the date, it couldn't have been very early. It, too had oversize bridge pins and the covering on the wire as it went through the oversize agraffe. It seems to me that more than one manufacturer did this, either experimentally or In their early manufacturing years so it wasn't a local aberration.
I have a feeling I may have seen this piano before, it's not every day we see a knot just like that one in the middle of the speaking length of a covered string and in approximately the same location. The one I saw was a Viennese style piano.