$250 for bare frame and fork is fine, but not a super compelling "must buy". The required 25 mm seatpost is a bit hard to find and can cost $50, so it's a plus if at least that is included. The fact that the seller isn't going to include those suggests he isn't going to deal on the frame/fork, but I'd offer $200. If he won't do that, I'd pass too.

These are cool frames, though. Back in the day, the Vitus 979 was a lightweight weapon for the pros, especially for mountain stages but Sean Kelly rode them to victory in all kinds of races. I remember they were pretty darned expensive in the bike shops, I want to say a Vitus 979 bike was $2000 in 1990 dollars. There were also carbon fiber tubed 979s (Chombi has one or two, I think :-) and later Vitus made the 993 with bigger ovalized tubes, either aluminum or carbon fiber (I have one of the latter).