That bag is very interesting. I'm thinking it stored something and was sewn shut, and then cut open. I'd almost think it was a protective cover for a replacement bag.
I'll make one last comment about the upholstery nozzle. It should be noted that the early 543/700 style and the 541 style are still not the same. The physical size of the metal nozzle is different. That makes for a total of 3 types from 1923 to about 1930. The 541 crevice tool I have is made of some type of plastic and if you look at it from one end it is off center compared to the metal and on center tool for a 543 and 700 and later models.
As you will see in the manual you got, the early attachment sets were much different from the ones we have. They were actualy more complete in some ways if I remember right. When I look at the big picture of Hoover attachments during that time period, I tend to think they devolved somewhat from the late 1910s to 1930.
