Scott #909-921 is called the Overrun Nations issue. Each stamp depicts the flag of a country that was overrun by the by either Germany or Italy during World War II.
If you’re looking for plate numbers on the plate blocks of this issue, you can stop. There are no plate numbers.
Instead, the American Banknote Company, the printer for this issue, printed the name of the country in the position where the plate number is typically located. Therefore, some collectors refer to these as the “name inscription” blocks.
Technically, they are not plate blocks because there are no plate numbers. However, most collectors treat them like plate blocks and refer to them by that name. If you order any plate block on this issue, don’t be surprised when all you get is the name inscription. You don’t need to return them or think that you got something else in error. They are perfectly normal.