The image which is going to be seen by the right eye is bound to be formed in the right side of the paper, or negative (inverted, but on the right half) by the right lens.
The images which is going to be seen by the left eye bound is to be formed in the left side of the paper by the left lens.
When you want to reconstruct the stereo image, you must show the image of the left lens to the left eye, and the image of the right lens to the right eye, or headache will certainly ensue, as - imagine being in front of a convex building corner - the right eye will see the left side of the corner and the left eye the right side.
The father, or grandfather, of an uncle of mine took stereo B&W positive pictures of the front during WW1 on glass plates. Those were to be seen through a stereoscopic viewer with two oculars, which looks like a binocular. The two images were impressed on a single glass plate, which was then put - once developed - into the stereo viewer.
No need to invert the two images, and no possibility either. And, by the way, the images are absolutely spectacular.
Maybe I misunderstood what you mean.
that's what I had originally thought having seen some original stereoscopic glass plates...