Yes, it is a tall price, but the defects, other than the adapted (or would that be: adopted?) rear sight are mentioned in the text. The auction is indicated for Germany only, so to my mind there might be a factor of indifferent picture taking rather than bad intent.
I find the setup of the sale just as poor as the rifle was fixed to work!
And, whatever is not clearly illustrated could be asked.
Clarity, or the acceptable measure of it, is in my opinion the ultimate responsibility of the potential buyer.
I once ended up with a rifle that appeared with more defects than I bargained for, but I took a risk based on similar pictures that did not reveal them or were mentioned in the text.
It is all in the game of trying to find that bargain or rare piece: you win some, you loose some.
But I would not be surprised to see sales of Falkes appear with a definite touch of sleaziness to them, like with so many other items of which a certain seller suspects it is worth it's weight in gold.