A couple of thoughts.
The Magna stocks are post WW II; the checkering has rounded corners instead of the pre war sharp corners and the medallion are the smaller post war curved nickel plated instead of the pre war 1/2" flat silver.
On pre war and early post war hand ejectors, the yoke does not have the serial # on it, only the factory assembly number.
The only other frame prior to the "Made In USA" stamped frames (which was ordered June 1922) that could have a 624XX serial number is a 455 HE, 2nd Model. The 1917 Army did not have a S&W logo on the frame. I think I see one on the left side of your frame, if not it's a 1917. Although the 455s did have the logo, it's larger and on the sideplate.