A nice pistol but quite old.
It needs to be filled with co2 and some people have the knowledge and equipment to do this.
Most people dont and many prefer the modern air versions.
So a limited market and you would be lucky to get £250.

But the modern air versions cost up to £1500 so if you can learn how to fill and use it you will have a pistol that you would possibly not otherwise own.
I have a friend who uses and loves an old co2 FWB pistol.
I will ask him to comment on this thread.