First "diamond" detail picture here -- [id=350935555]
Second "diamond" detail picture here -- [id=350935645]
Full base embossing picture -- [id=351006158]
Full profile picture -- [id=351006365]
- The following information was provided and answerd my questions.
Saw your photo and question about the American beehives. I've specialized in Americans, along with other Oakman-related insulators, for many years so I'm very familiar with their quirks.
That little diamond or character made up of four dots (at least, that's how it looks to me) is on all American beehives. You'll also see it on the two-date CD 156.1s and the 160.7s. I don't know why that character wasn't added to the special insulator font that Bill Meier created for the price guides; I guess he just didn't think it was important enough.
Anyways, you definitely have the  embossing. Sorry to hear about the damage on the top. I'm pretty sure yours had either a V or an I as the top letter, since that's all I've ever seen for two-date beehives. The V has a very distinctive shape and a wide groove and is a little taller than the I molds. I might be able to tell what yours is if you post or send me a photo showing the profile.
The only American beehive that's turned up without a letter on top is the  "American Insolator" variant with the embossing errors, and there are only a handful of those around.
Hope that helps. Feel free to ask more questions, especially if I've just created more confusion!
Happy collecting, Bill Snell
*** Original Post *** I obtained my first American Insulator Company beehive (CD 145) and when I looked it up in my 2007 price guide I noticed that none of the EINs mention the lazy diamond shapes in the embossing. So here is my list of questions: Do all AIC CD 145s have these diamonds in the embossing? Are the diamonds specified in the 2011 price guide? Do the AIC 143.? have the diamonds also? Are there any photographic studies of the AIC base embossing variations?
Here is my embossing:
(diamond) AM. INSULATOR CO. N.Y. DOUBLE PETTICOAT (diamond) PAT'D SEPT. 13, 1881, NOV. 13, 1883.
This leads me to call it an EIN  BUT, I cannot tell if there was a letter on the dome or not, due to some damage, exactly where I would have expected a letter. :(