bobski,, I'm not sure what you mean about a 5 screw Ruger?
The 3-screw guns are the Old Models,, where the 3 screws we discuss are the action screws in the sides of the main frame. The New Models use a 2-pin set-up for the action parts.
There are 5 screws on both models that hold the grip frame to the main frame though.
But,, as a collector,, we prefer unaltered OM,, 3-screw guns. But if we find a "converted" Om that has the "safety upgrade" parts we will buy them at a reduced price because we know that to return them to "as shipped" condition the parts will cost us $100-$250 depending upon the model & such.
When we use the OM's as shooters,, we know that for safety,, we only load & use them in a safe manner. We "Load one, skip one, load four,, fully cock the gun then lower the hammer onto an empty chamber."
Most of the OM guns I've handled that had the safety conversion parts,, the action was a lot rougher than original. They work just fine,, just rougher actions.
Now,, if you are thinking of the S&W 5-screw guns,, that's totally different.