There is another instance where you can find 00 stamps, or at least publicity photos of them. Here are some examples, along with the issued design which was also sent out as a publicity photo.
Publicity photos really started in the late 1940's. Until that time, the USPOD would send out a postcard announcement to magazines, newspapers and collectors who had subscribed to that service. That ended in 1947.
After 1947, the publicity photo was mailed to the same groups of people as the cards, except for collectors. They were not on the mailing list any longer. The only exception would have been the cachet makers.
About 1982, the first series of publicity photos appeared with "00" where the denomination was supposed to be. It was either that, or more frequently, no denomination at all.
There are four types of publicity photos, not including size difference. Black and white photo, color photo, color transparency and projector slide formats.
The following shows both the black and white photo and the color transparencies for two stamps from the Great Americans series of the early 1980's. I've start each group out with an issued stamp for comparison.



This is the more common type, where the denomination is simply left off.




You will note, in the about four images, the issued stamp, the "00" black and white photo, the issued design complete B&W photo and the color transparency of the finished design.
There are a couple of reasons why these occurred. They almost all occur when there is a rate change, either just before or maybe afterwards. The reason for this is time. It takes several weeks to months from conception through final approval to create a stamp design. If it is started, say in the period of the 20 cent rate, but the rate changes to 22 cents, the designers may leave it black or assign the "00" to placemark where the denomination of the stamp would appear.
Another reason is shown in the next example. This is an proposed design which never occurred. It is on a postcard which was mailed to drum up support for the stamp designs proposed. I think they would have made for some interesting stamps.

Finally, the computer became a force within the Bureau of Engraving and Printing (BEP), and later civilian contractors, in the creation of stamp designs. The following is a working model of the design which would have been presented to the Citizan's Stamp Advisory Board or the upper echelons of the Third Assistant Postmaster General's office to gather comments prior to final design submission. This format also spelled the death knell of the publicity photo and photographic essays, just as the photograph had pretty much eliminated the printed essay and proof formats.

The last publicity photo appears to be for Scott 3961-64, which is also the last 37 cent stamp.
I have been actively pursuing these for the twenty-five years. I have never seen a publicity photo issued after that one. If anyone happens to have one for a design after 3961-64, please post an image of it. I'd like to include it in my database.