Bit steep to my mind.
IMO It's just a fancy paint Stainz set..... plus some extras. Collectors are often funny birds. If they are selling it's almost always pricey, if they're buying they'll usually nit pick you to death over nearly invisible "defects".
If you want to RUN it you'd probably need to add a 2017 to pull the tender and freight cars and let the Stainz pull the coaches on 2 loops (or automate it to alternate with a siding like they do in O scale).
It's your money, but I'd talk to the guy and see how "firm" the price is....and maybe offer him half that to start.(maybe 3/4 if you really want it)