1. 1955 model did not have the number "1" or the "!" - as I guessed, you can get the 1 with a lower-case L. But the exclamation point stumped me - turns out you had to use apostrophe, then backfeed a character, then use a period over the same space to recreate the "!". 2. Different typewriters had different typesets that could result in dramatically different script lengths for writers. It forced one of the screenplay writers of Star Trek to have to tighten up his script substantially after they realized it was too long.
The site looks well done and I think the Manuals and Repairs section might come in handy.
So a quickly typed letter on an old ribbon has a unique character that can’t be reproduced by a font.