Congratulations on the fine typewriter!
Looks like you found one in truly excellent shape. I love my Urania, which is one of the war-time production ones with thicker duller key rings and a plastic top cover (the high collar you write about). Mine was made in 1942.I love the access to the mechanics, and you may be right about it being built from parts for office models, that makes a lot of sense.Side note, tabs are used for lining up text in places other than the margin, like an address on an envelope, and shouldn't be used for indenting paragraphs. That puts more wear and tear on the tabulator than would be normal. Indenting should always be done with a space bar, even on a computer (and when you submit text for publishing there is a huge difference in how the file is compiled for tabs vs. spaces and formatting can get icky fast). This machine is teaching you good habits!
Thse are interesting, quirky portables. I have one that's been awaiting repair for many years ...I have never heard Mark's advice against indenting with a tab. In digital texts, I know that many publishers insist on indenting paragraphs with tabs!
Any time you publish anything you want to pay close attention to the style guide. You may be right that most publishers prefer tabs. Maybe the vast majority. It is certainly true at least some prefer spaces.
Another excellent write-up. Just a beautiful typewriter - that high collar is fantastical. "Obscene segment" - ha!