In my copy of TGT there is no "DD" with this mold, but there is a "DO" with the Diamond mold. Looking closely at the hot-stamp, it looks more like "DO" than "DD". I wouls appreciate other opinions (Gene) who have seen these letters on other chips.

BTW-"DO" is attributed to: S. 4th St., Savannah, IL, Open 30'3, Closed 40's. This is the same as the "LC" chips!

Jim