
first stamp left to right

third stamp left to right

What makes me think that a new plate was introduced in 1949 is that the issues from that year, the 2C or Straight Rays, share plate varieties with the later issues, and the issues from 1948, on the unwatermarked opaque paper (NOP) and before do not.
Here is a 2C with the variety with the outer line upper left corner clipped

detail

Here is a variety I found several years ago as well as in the large lot I have been exmining lately. I only find it on the 1L3 from 1955, the printing with a bright yellow background.

