I had a typewriter in the 60's. It did NOT have a key for the number "one". I used lower case letter "l" instead just like on this document. The red circled number 1 could have been added later. Why? I don't know.
It just depended on the typewriter. Googling images of “old typewriter” and “1960s typewriter” will show you that some (maybe half) had “1” keys and others did not.
I would think this was based on two factors: compactness (was it a portable unit intended for lugging around?) and expense.
For a government office, of course, nothing but the best would do, especially in a major office. After all, it’s on the taxpayer’s dime. I would expect a major city registrar to have “1” keys on their typewriters. I would expect this to be equally as true on Australia as in the USA. The one place where it *might* not hold true (emphasis on the *might*) could be in Mombasa. But again, that was a major city (for Kenya, at least) as well.