I'm out and about an need some info on a 16sz Illinois 167 adjusted 21 jewel.

The only grade 167 Illinois watches made were 17 Jewel. Guessing that you may have meant 21Jewel Grade 176;
Model 5 (Getty) Burlington Watch Co, 4 adjustments, Tu-Tone Gold inlaid and highly damaskeened movement LISTED AS RRG, total production 190 all in 1 run in 1908.

You where correct it was a 17 jewel. 17 sure looks like a 21 upside down. #5557962

5557962 is 1 of 2000 Illinois Grade 167L made by Hamilton in 1932. Of the total 3500 made in grade yours is the last of three separate production runs from 1928 (before Hamilton) to 1932. It should be marked 167 or 167L on the bridge. It had a combination of friction set (press fit for the balance staff) and brass fitted set jewels in the 17 Jewel movement and is marked "Adjusted" but that was only for Temperature and Isochronism.