Laurenz van Gaalen wrote:

... the SM9 was also offered with reverse carriage (for Arabic), was this also possible with the SG?

By the early '60s Olympia had sales centers in over 140 countries and offered myriad variations of the standard typeface and keyboard, including characters for a number of different languages. I don't see why there wouldn't have been a reverse carriage SG1 given the number of countries and languages (see below) that are written from right to left. I know that I have seen more than one Arabic SG3, but don't recall whether I've ever come across a SG1.

Arabic
Aramaic
Azeri
Divehi
Fula
Hebrew
Kurdish
N'ko
Persian
Rohingya
Syriac
Urdu

This one kept me busy this week... such fun to bring one back to life :

Fix To-Do List : 1. Cleaned exterior.2. Cleaned interior (used 1 full can of PB Blaster)3. Polished all chrome trim and pieces.4. Polished all key-tops and other plastic knobs.5. Straightened out body panel in front of space-bar that was bent.6. Mounted new ivory-colored space-bar.7. Fixed Tab-Clear key that would not return.8. Fixed line-spacer dial (on left side) that had no spring-tension.9. Lubricated paper-injector and mechanism to get rid of noise.10. Polished clear plastic paper guides.11. Polished up replacement paper support and mounted on machine.12. Resolved all sticky type-keys that do not return 100%.13. Replaced 4 rubber washers at frame/body interface.14. Cleaned and treated platen rubber and feed-roller rubber.15. Touched up body panel paint.16. Replaced white rubber grommets on ribbon cover.17. Replaced plastic spools with metal spools and new B/R ribbon.18. Resolved “stuck” space-bar linkage issue at escapement interface.19. Replaced and/or re-attached interior felt pads as needed.20. Added peel & stick felt padding to interior of ribbon cover.21. Cleaned &lubricated ribbon color selector dial & touch control dial.22. Cleaned rubber feet and treated rubber pads.23. Lubricated carriage rails. Lubricated escapement.24. Replaced draw-band and adjusted main spring tension.25. Fixed bell and right margin line-lock malfunctions.26. Re-applied red enamel paint in-fill for “Deluxe” badge at segment.

Strange that the paper support wouldn't lay flat when mounted correctly. From the sounds of it, that's probably a wise decision when it comes to the reverse mounting. Here's hoping that it stands up (pun intended) to many years of interactions with your furry feline friends.

Your problems with the paper support not lying flat intrigued me, so I looked into mine. It was lying flat just fine but I was surprised to find that I had mounted it backwards. Now, that bothered me and I wanted to check into your problem, so I turned it around to the correct orientation and it still lies flat. Both ways are freely pivoting and both allow it to move about the same---good support and lying flat. 'cept now I can read the numbers and the stop at the top will curl the paper when it hits, for an extra hint that I'm done with the page.

The one possible difference is that the one on my SG1 came from an SG3. I don't have an original SG1 paper support to compare but they sure seem the same from what I can tell. You had a good idea to check the hinges, though it seems to me that if they are out of position enough to affect it one way, they would affect it the other way, too. Does the up position rest at a different angle?

And when it is mounted forward-facing (i.e. correct position), it stops at about a 55-60 degree angle in its full up position :
.