I am seriously considering buying a nickel .32 S&W Long from a friend. The piece has a 3.25? inch barrel and a serial number 6730XX. There are three screws on the right side of the frame and a flat cylinder latch release. Its bore and six chambers are super bright and, though there's a couple of rust spots under the grips, the revolver is very clean. Anyone know for sure what I'm looking at, what it may be worth and when it was made?

Is this an I Frame? If so, are J Frame grips and adapters interchangeable with this piece?

What is the difference in the more modern Models 30 and 31?

Thanks, CW3RDL