As a general FYI to all.
Electric typewriters were around since the mid 1930s and were well available by the early 1940s.
The IBM ‘Selectric’ with the chrome ball came out in mid-1961. Unless Hawaii was buying brand new typewriters in 1961 it is unlikely the DOH was using an Selectric.
So electric typewriters that could type with some consistent pressure and create somewhat uniform looking letters were around for a while.
http://en.wikipedia.org/wiki/Typewriter
http://en.wikipedia.org/wiki/IBM_Selectric_typewriter
Could these electrics be consistent enough to generate a letter that when encoded via a digital document archive system using single bit encoding that the letters would be down to the pixel exactly the same? That is hard to say. But with single bit encoding you get either a 1 or a 0 or a black pixel or a white pixel. Since no shades of gray are involved an exact duplicate may be more possible than if gray tone or color encoding was used.
Suspicious anomaly - yes.
Proof by itself - no.
No it's not hard to say. If the image pixelation is reasonable for archival image storage, it is very unlikely. There will be some probability of having two letters in different places have the pixel pattern, but that probability is low. How low?
Experiment and find out! That's my advice. Attempt to duplicate what the process history of the proffered image might have been.
It would be helpful to know which models of equipment that department Hawaii used over the years, and certainly in 1961.
The alignment of tab stops, of inter-key-impression, interline gap and typefaces in the Nordyke and other COLBs of that era are good data set to start with. That should narrow down or suggest a particular model.