That's awfully good looking, but you're right it's had some rework and has a post 1935 commercial large logo on the side plate.

First thing to do is pull the side plate and confirm the # stamped on the inside is different than the 22600 in the yoke and yoke cut in the frame (Colts have cranes, S&Ws have yokes), or no # at all.

Use magnification on the eagles and you'll see an eagle head pointing upwards with the S24 and S2 underneath; they're inspection stamps.

Second, pull off the left grip and check for a date stamped on the left side of the grip frame near the toe and an R S near the heel.

The marks with NP on the barrel is anybody's guess but maybe a civilian mark or rack # for a guard service, private or Govt agency, or etc. A close up of the marks would really help. Also a shot of the other side.

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Jim
S&WCA #819