I agree with H Richard
This is a pretty nice looking early- to mid-1920s, nickeled M&P with the 5" barrel. Everything looks good and original. If you can get it for $400, great. I would not pass on it for a mere $50 more.
Probable date on this one is between mid-1922 and mid-1927.
Sorry. Just saw that you posted the serial number. I was going by features only. So the shipping is closer to 1923-24. Still in the range I suggested, but at the lower end.