Welcome to the forums from the Wiregrass! Your 38 M&P dates to around 1930. If the asterisk is actually stamped on the gun, it went back to the factory at some point for work. Take off the grips and look for a date in the format MM.YY stamped on the left side forward toe. Also, there may be a B (or N as you don't say what the finish is) stamped on the left side to indicate a refinish.