Like all 327 guns no clear cut answer because , like you said , not many being bought and sold.
Not a common gun but not rare. Not common because sales were low so they did not make any more. Suffers some from not many looking for one either as it is a large gun for the caliber.
Barrel length will determine value and many prefer the half lug Lippsey's.
Does not sound like I like them but I do and have a 4inch. They are a great way to wring out the most from the 327while staying in a DA.
If presented with a chance for a 6 incher at a non inflated price locally I would be all over it but not jump thru hoops to get one.
So value ? I guess it depends on if you find someone LOOKING for one.