I sold 2 of my 3 relatively new( only few years ago) German made zeiss vm/v 3-12x56 FFP for approx $1300 each but they were in perfect condition in every way and not very old(probably less than 5 years old at the time ). It also took awhile to sell them.
I kept one of those scopes as they are simply a fantastic scope.
As per your Swarovski:
It largely depends on the condition of the glass , the exterior of the scope and the AGE of the optic .
From your description it sounds like it is at least 15 years old and maybe more( if it is one of the really old ones which requires locking the turret with a screw it will affect the price significantly). It also sounds like it is marked up quite a bit. Based on that I think you would be in the $800- $1000 range . Now, if it is less than 15 years old and in mint condition( including glass) I think you would get about $1300.
In the end it is worth what someone is willing to pay for it....