Unless it's a fiber tag which usually means ww2 issue, the styles and colors are all over the board. Some city's used dated every year and some didn't. Style's changed, more than likely when they went to a new supplier. Colors would change to contrast years but no rhyme or reason to it all.
If you look at the left side of my display, you can see the larger plates.most from the 30's. The majority are the smaller sized plates, and as mentioned,I've never noticed any correlation between years and colors.