[Ron Wood]

Alf,
I would expect that there are variations. After all, it was printed in 4 languages and probably more than one printing during the time the Model 1906 was produced. I have not seen a great many manuals, but generally they are of the format and construction I outlined. I would be very wary of any copy printed on modern bond paper. Also, generally reproductions are photo copies. So unless the copied original was really mint you probably will encounter images and text that not as crisp since they needed to be "photoshopped" to remove stains, creases, etc.
With the item in hand, a good archivist or conservator can spot immediately if a document is original. Unfortunately, I make no claim to that level of expertise.