Value for a Western Field, Model 31A, 22 Cal.?

My dad left me a Western Field Repeating Model 31A, 22 Cal. L.R. Pat'd June 6 1932.

The gun has no serno. It has a 23 1/16" long barrel and the steel is all blackened with some blemishes. The stock is in fair shape with few scratches and a crack at the forearm running from the trigger housing forward for about 8 inches. The butt-plate is in good shape. The bore has no pits, etc.

I'll be leaving this gun to my son and am curious as to it's value for both insurance and sellable value.

Thanks for your help.
Tom