The first offset stamps I find are from 1941/42 and type A (round jacket). All are red brown. The regular issues seem to be printed on the 1E3 paper:
The officials also seem to be printed on 1E3 paper, but this paper is thicker and the watermark is somewhat diffused.
I find a darker shade of this stamp in 1946, but only on the officials:
And I find the regular issue dated 1949:
I need to continue to look at these offset issues to verify how many distinct issues there are. The main question is if the stamps dated 1946 and 1949 are separate issues or late usages of the 1941/42 issue.