Yes. The dash 1 indicates it is a J frame revolver. Prior to 1961, the Regulation Police revolver was built on the older I frame. In that year, production switched to the slightly larger (overall) J frame and I frame production ceased. So a Model 31 is an I frame (actually a so-called "improved" I frame with the coil spring), the Model 31-1 is a J frame.
Jack
Those are good shooting revolvers.
I like mine.
Does yours have the 2", 3", or 4" barrel?
Measure the barrel from the front face of the cylinder to get the correct measurement.