Everything depends on Age, Grade & Condition, and whether or not there were any modifications to the original gun. Excellent condition to one means good or fair to another. With most Smiths ... like Parkers, Foxes & the like, the amount of original case colouring on the receiver and other parts means a lot in terms of value, as does the condition of blueing & the wood. An original, good condition hammerles, sidelock, fluid steel barrel ( as opposed to damascus) may go for as little as $ 500 to $ 600 for a common field grade with extractors. Auto ejectors and/or single trigger can add $ 500 apiece.
There is generally a considerable premium expected for gauges other than 12, with 16 gauge adding about a third, 20 gauge about 50 to as muchn as 75 percent and 410 three to four times the value of a 12. You really should get an appraisal by someone knowledgeable. ( who doesn't want to buy the gun themselves !!! )
