I referred to the N series as having bellow straps. Your photo now is of the D series, That has the internal bellows locking mechanism.Well, it is a bit audacious to claim what is "original" in an instrument specially built for a single person. Here are photographs of the same person with his final instrument, and on the bottom you can see that he has the same kind of strap mounts on the top of his last instrument as there are on the one I have in my possession. It doesn't look on the lower photograph like he'd be playing rather than lecturing and I see no actual straps.
Also, that instrument seems to have a regular air button opposed to mine.
I don't believe it came originally with these two screws and rings, but I have not actually worked on one of these. I have worked on the Morino M series (piano accordion of similar age) and these at least do not come with the screws and rings. In any case, these screws appear to not serve any purpose other than preventing the celluloid from touching a hard floor.
As for the term "original", I would interpret that as how the instruments were delivered in their "standard" configuration. If something is specially built or altered for a single person it is not "original" as in how the whole series is produced. The standard on these accordions for the shoulder straps is the "curtain rod" top and bottom. So the additional straps are not "original".