According to Blue Book...
Acknowledging the limitations of that source, Blue Book of Gun Values shows prices ranging from $1,200 for 100% condition to $120 for 10% condition, with an added 20% for original box and tools. At 80% condition, they list a value of $375.
I add the note about limitations because Blue Book often fails to make distinctions for variations that could add or subtract value for a collector, such as whether the gun is built on the "improved I frame" or the later J frame, whether it has a round but or a sqaure butt, etc.
Also, an estimate of 80% of the original bluing would place the gun in 80%, if the gun is in 100% condition mechanically.
Many folks - if they're looking at buying or selling a gun - will also look at what such guns are selling for at sites such as GunBroker.