Be sure to check out all three pictures...

Here's a picture of one of the 162 insulators I bought the other week (cost me .91). This is a CD 231 and mine reads: (F-skirt) HEMINGRAY -820 (R-skirt) MADE IN U.S.A./ 11-51 CB.... Clear....Now, if you look at this CD in your price guide you won't find an option for this particular embossing. Mine is missing the word 'TEMPERED' on the front skirt and there are no dots on the rear skirt.

An answer/theory from Bill Meier on this one: and I quote: "My piece is marked 4-51. (note the dot) on the back. That means the mold was made in 1951 but the insulators were produced in 1952. You will notice yours does not have the dot so it was produced in 1951. Given this limited data, one might be able to conclude that they added 'TEMPERED' after the original mold was made. The 1951 run didn't have 'TEMPERED' and the 1952 run did...On my piece 'TEMPERED' is smaller in height than the HEMINGRAY -820, perhaps smaller to fit in between HEMINGRAY and the base? Just conjecture at this point..."

Thank you so much for the info. Does this make it into the new price guide coming out soon? :) Happy collecting...!