Well you haven't given any pictures, presumably to hide what you have found, which is fine with me.
My perspective is coming from owning a Linhof Schneider - Kreuznach Tele Arton f/5.6 250mm lens mounted in a Compur 1 shutter. It is in excellent condition and going on my serial number, was manufactured in 1973. I live in Australia where photographic stuff like this is quite expensive. I bought this lens about 4 years ago for about AUD $250. The shutter had an issue, hence the cheapness, a service costing AUD $170 was done and now it is excellent. Allowing that a standard clean and check would have cost me AUD $120 the shutter cost me an extra AUD $50. Therefore cost to me was AUD $300, if you get my drift.
Usually in this country, these items can and did sell between AUD $300 to AUD $400.
On international selling sites that was a reasonably hot price if it was a USA sight, about right for Germany, cheap for the United Kingdom though. It also depends how the market is right when someone is selling and someone is purchasing.
My take is that what you are considering could have been manufactured in the 50's, if so I would think a Tele Xenar would be around USD $250 to USD $350.
I would factor in a service on the shutter and lens, more so if it is in fact from the fifties.
Mick.