Would have been a great bike in it's day, it was on my wish list before I went down the Rohloff path.
That one looks like it's had a hard life and would have benefited from a bit more TLC. I wouldn't consider spending that sort of money till I'd reassured myself that it was only surface rust. Even then I'd consider the price optimistic, you'd have to really want it. For comparison, look at the thread where gepabu asks if his almost immaculate Audax was a good buy for £400.