Hello Gerben,
Thank you for the interesting price list, useful reference point.
I agree with you that 12000 euros is too much, 6000 should be optimistic.
I would like to highlight that the price is incremented when Mauser ended the Parabellum production on 1999.
I have recently seen some late IWA engraved and gold-plated around 7000 euros (with all accessories, case and so on).
I think this gold-plated Sport-model rarer than an IWA engraved one for few reasons:
1. The sport-model itself is a quite rare Mauser Parabellum even without special customization;
2. It was made in the 1975, about 20 years before the late engraved IWA.
3. I think this model a unique piece, made by Mauser as special order.
I think 7000-8000 euros an adequate price.
This is only the point of view of a Mauser Parabellum enthusiast therefore not an impartial judge.
Ciao.
Mauro