"I am not a Colt SAA historian,I might be wrong,but I have read there were more 32-20 SAA's produced than any other cartridge( Back in those days)"
No. .45 Long Colt was by far the most produced, followed by .44-40.
Third in the list, though, was apparently .38-40, and a close fourth was .32-20.
Regarding "old west" handguns, realistically any handgun to be found in the east would be found in the west.
But here's an important distinction... despite what Hollywood would have us believe, not every man, woman, and child walked around the "old west" with a pair of Colt, Smith & Wesson, or Merwin & Hulbert .45s in hand tooled Mexican Concha holsters.
By far, probably by a factor of 10 or more, the most popular guns in the old west, and literally across the country, were the smaller solid and break top revolvers chambered in rounds like the .22 Short, the .32 Rimfire, the .32 S&W, and the .38 S&W.