For the magna style stags, that factory wood style came out in the 1930s as an option on K and N frames, but didn't become standard or overly common until just after WW2. Stags were very popular in the '50s and '60s. The factory walnut set with S&W medallions was used from the very early 1930s until the U.S. entered WW2.
As for the spacers added to the factory grips, that was at least somewhat common for shooters with big hands. I have a couple, and also have an N set with walnut veneer glued on the back to make them wider.
I don't speak Colt (only own about a half doz), so all I can tell you about the pearls is that it looks like the shape and locating pin hole for a Colt.