Some of the Pachmayr adapters that are being offered were intended to fit Detective Special's that had the old Police Positive/Police Positive Special square butt frame. Colt didn't make any changes in the butt's configuration between 1933 when they changed from the square butt to one with rounder lower corners, to about 1966 when they changed to the so-called "short frame."
However it is quite possible that an individual revolver might be slightly different because each frame was hand polished. Last but not least, I have also noticed that Pachmayr grap adapters are not always perfect fits - in particular between postwar and pre-war S&W 1905 Hand Ejector/Model 10 revolvers.
Remove the little screw that holds the retaining clip and then wrap some sandpaper around a wood dowel. Go to work on the inside radius, and when the fit is improved reassemble the clip and you're good to go. Check the fit while the stocks are on the frame. It is the adapter to grip fit that's important.