There are very small differences in frame tolerances from old school, to new school, to custom frames. Very small.
I don't know if the S&W have a "longer" or "larger surface area" of their rails than other makers. I have never heard that before, but anything is possible.
You may hear someone saying they have a "hand fit, tight rail" 1911.
What they have is a fit between slide & frame where the gunsmith has put the rails of the frame in a vice and squeezed them, or spread them, just enough to make sure that the fit to the slide is "perfect".
This takes a rattle out of a gun that doesn't have the tightest tolerances. It's pretty common in the rebuild, or piece kit, builds.
The custom houses usually have their frames and slides CNC cut so they have that tight fit already.
If you have a micrometer, you can spec yours and some of us can spec ours and see what we come up with. *shrug*