Stanley Gibbons lists these as normal (Estonia, German Occupation, 6-11 - it is a set of six). Around twenty years ago a local dealer had an imperforate set but, alas, I could not afford it in those days and have not seen them since. There are also overprints 'EESTI POST' which are genuinely B.O.B. (i.e. locals and not in standard catalogues) but I have never seen them either.
The truth is within and only you can reveal it 19 Apr 2019 08:34:01pm
re: Estonia: B.O.B.?
Below is a complete perforated set of the occupation stamps being discussed.
There are also two of the imperf stamps (20+20 and 30+30) of the set.
Below them is another set of German occupation stamps from the second World War.
The earlier set is quite common and has a low catalog value. The second set is
more scarce and I just recently obtained these at auction for around $20.