Don't know if this was what you were looking for, but here goes. I can tell you where you'd find them on a modern S&W M29:
Three holds the sideplate on.
One for the grip.
One for the thumbpiece.
One for the mainspring strain screw.
Three for the adjustable sight (elevation, windage & one on the topstrap of the frame).
On the older S&W, there were four and five screw models. New ones, like the M29 are three screws and this is in reference to the three screws which hold the sideplate onto the frame.
Four screw models had, you guessed, four screws to hold the sideplate on. The fourth screw was located near the top of the sideplate in proximity to the hammer.
On the five screws, the sideplate was like the four but a fifth screw, which had nothing to do with the sideplate, was found in the trigger guard. It served to keep the cylinder stop spring (and plunger?) in place.
