Liesegang Tachyskop 23 lens general questions

Good day,

I bought an 'ED. Liesegang Düsseldorf Tachyscop 23' at an auction last weekend (Back focus length aprox: 34cm, F5.6). It was a bit of a gamble as it didn't seem to be that neat and the lens hood appeared missing. However, I just restored a wholeplate camera on where it would fit nicely, so I took the chance. When it arrived, it was completely wrongly assembled and pretty dirty. Both problems were solved within a few minutes and the lens turned out to be complete including lens hood, SCORE!!! The first picture showed how it was presented and the second is how it looks now.

Now I have two questions:

1: I already read in another thread that it is a Rectilinear/Aplant and this is confirmed by the reflections in the rear group. But approximately what period would this lens be? I was thinking of the years 1890-1900 myself, but unfortunately I can't find a serial number registration (#20796). Because the lens has a waterhouse cutout, I am starting to doubt whether it is older, in this period most lenses of this caliber already had an aperture? Or am I wrong? It was of course not such a luxurious brand as, for example, Voightlander.

2: A previous owner has tried to polish the lens but has damaged it quite a bit. The lacquer layer has been sanded off and quite a lot of patina has developed. Now I wonder if it is possible to lightly sand the lens again (grit > 800) and then provide it with new lacquer? because I don't want it to look too new again, and that will probably be the result if I do that. Is there a way to make it look a bit neater without it getting too new and shiny? I've heard about things like potatoes or toothpaste, that make the patina less dark and it remains a bit more authentic. Does anyone have experience with this? I don't want to damage him any further.

Thanks in advance,
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At first I thought that what turned out to be the lens hood would be one of the first types of iris/diaphragms. I once saw an old lens that had that, it also had a kind of bulge in the lens shaft that looked a lot like this. But luckily it was the lens hood that was turned on the wrong way. Also, the middle thread of the lens was twisted skewed, so it didn't fit nicely, but luckily nothing was damaged as a result. I just tried it on my 8x10 and it does have a bit of a petzval twist, maybe there is still an element flipped over (everything fits everywhere).

That looks like a great lens. It would be really nice to see some photo’s taken with it.