I cannot say, it was acquired that way, back in the 1980s. While the wear, etc. IS generally consistant, the possibility of such a reconfiguration is - as you point out - always present.

That said, given my choice, I'd much rather have one with the short stock - which is, after all, the rare (and fortunately unfakeable) part; otherwise, it's really just another 1899, albeit with one with a bit of a cachet, and the hint of mystery.

Another way of looking at things (even if only stockwise, since there is ALWAYS the number issue) is that a short stock MIGHT be original, whereas with the long stock you KNOW it has been changed (but when, and by whom?)

It's a slippery slope any way you look at it; too bad the number data is so thin. The vast majority seem to be in the 118k and 119k areas. Outliers like mine get a raised eyebrow from the git-go, though there IS a small cluster there.