Ron, One way to determine value for one of these is to find a boat catalog and look up "boat Anchor" Compare weights, say a ten pounder. This should be fairly accurate but may not reflect actual market value.
Watch out for re-finished and rebarreled pieces, these were produced by the thousands. Often the safety is broken or dosen't work. You simply must have a manual. It is similar to a tractor transmission and goes back together just as easily.
Oh! Have I forgotten to mention that if it has been rebuilt and has some inferior parts the bolt can become a rearward projectile and end up as eye wear, not very stylish.
I have had several over the years and there are many sharp projections all over the pistol, particularly inside the chamber at the bolt face when you are trying to pry out a jammed cartridge, I threw it into the clothes dryer with a bucket of rocks and it smoothed it right out.
Be sure to rent one for a week or so before making a buying decision....

Jerry Burney