For some reason you neglected to mention the C prefix in the serial. They didn't just put it there for fun and it makes a difference.

That's a Military & Police Model from mid 1950s. In 1957 this gun becomes the Model 10.

This one looks like it has seen lots of use. Condition is pretty rough with deep scratches (rust showing through) corrosion and "freckling" in the finish. Hard to be certain from photos but it may have a 5" barrel which is a little more interesting than the more commonly seen 4" and 6" versions.

A 5" M&P is a cool gun but the condition hurts value. To me this is a $200 pistol.