You have a ".32 Hand Ejector Model of 1953" if it has a round but or a ".32 Regulation Police Model of 1953" if it's a sq. butt. After 1956 they have a 3 screw side plate (one under the grip). Both built on the "NEW" I frame which uses grips the same size as J frames.
These are known to collectors as 'Pre Model 30 or 31' because those are the model numbers they were assigned June of 1957.
Yours was produced in 1957 or 58 and is worth $150 to $500 which you can fine tune by estimating its amount of original finish or if the box, docs and tools are with it.