You need to provide more information about the pistol. Is it a hammerless revolver or a top brake 5 shot? What type of grips? All I can tell you with the limited information provided is that if the letter M precedes the serial number this indicates that it's a target pistol. The letter H could mean that it was manufactured between 1915 and 1941 but without more information it's hard to tell. I wish I could be of more help.

Thank you for the additional information. The 3" barrel tells me that the letter preceding your serial number is the letter H which means that it's not a target revolver. Iver Johnson began stamping letters preceding the numbers in around 1903. The letter H designated this to be a small frame top brake hammerless .32 cal as you already know. The company manufactured about 3000 to 4000 of these revolvers a year and given your serial numbers and the flat hammer spring which they began to change to a coil type in 1915 I would estimate that your gun was manufactured sometime between 1914 and 1916. To restore this gun for a conversation piece is a great idea I would not recommend trying to fire modern ammo from this gun. I hope this helps you. Good luck.