It is about the "space"/ "no space" on the Joliets...

but on $2.50 Shreveport roses - it is dark/ light inlay.
$2.50 Tunica Chipcos - dark and light surface
$2.50 E. Chicago - $2.50 - Reverse inserts (I guess) and
$2.50 Reno (purple) - it is about "dark" coloring in the "a"'s of Harrah's.