That's a fixed sight K frame .357 Magnum, so it's a Model 13. It's built on a three screw frame (the third one is under the horn of the grip panel). The barrel is 3" long and it has a corresponding round butt grip frame.
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Since it has a non-pinned barrel and an early alpha-numeric serial number, it's almost certainly a Model 13-3. Swing the cylinder open and look in the frame cut for the model marking. It dates to the early 1980's.
It appears to be in excellent condition, so it's probably worth about $600.