The Sangamo has become one of my favorite grades of Illinois watch. At the time, this was the second highest grade watch Illinois made-behind the 189, and is thoroughly well finished throughout.
There are a whole bunch of variations in these, including several different damaskeen patterns and several different marking variations.
I've managed to put together a small collection of three Sangamos covering three of the more common variations. This collection is by no means complete, but none-the-less I think is representative of some of the more variations. My three include the 23j "wavy stripe" two tone pattern, a 21j bright spot "adjusted" version, and a 21j "Adjusted 6 positions" version.
I also show the dials, which I believe to be correct for all three watches at their respective serial ranges. Please note that there are quite a few subtle differences in the styles both of the numerals and the signatures of these dials. Also please note that the hands on the bottom center watch are clearly incorrect :)