Any following letters are modifications to (variants of) the base gun.
Model names are all too frequently a source of confusion for Star pistols. The right place to find all older Star pistol model numbers is on the butt, as seen in the illustrations below and photo to the right.
Especially for the older pistols, there are just a few tips you need to know to almost always find the correct model of your gun. On the flat plate on the bottom of the gun, just rear of where the magazine is inserted, look for a letter, set of letters or a word.
First of all, there is simply no such thing as a model SA, or S. That is part of the company name, and means "Anonymous Society," (Sociedad Anónima). The longer number is your serial number, incidentally.
If there is letter code, the first letter is always what I call the series.
These are all the year coded, Spanish government issue pistols, like the Model 1922 and Model 1940.