Yes, if I understand correctly what you are saying.There's a screw in front of the trigger guard. 3 visible screws and 1 under the stock makes it a 4 screw, correct?
1. The cylinder stop plunger retaining screw in the front of the trigger guard.
2. Forward screw in the sideplate.
3. Sideplate screw immediately behind the trigger guard.
4. Rearmost sideplate screw is hiding under the right stock panel.
The fifth screw that was eliminated in 1956, was in the sideplate at the very top, between the hammer and cylinder and just below the rear sight.
An interesting sidebar: The original Model of 1899 and the Model of 1902 until 1905, also had only four screws. But they were all in the sideplate. The screw in the trigger guard didn't exist until 1905, when they reengineered the cylinder stop.