It takes less than a minute to take a rear sight off an arty barrel.
The leaf is held on by a single small pin, and it is easy to drift out.
My point is a complete barrel with sights would not be much of an impediment to attach to a receiver. JMHO.
Finish reaming the barrel for headspace after installation would take much more time.
Doubs,
I have all 4 variations of 1917 L P08 sight configurations myself; they are not tough to find;
just pay attention to the pictures of the many 1917s on auction.
I made it a goal to have an L P08 of each year, with each major external variation and also those with the 1920 PS.
As I noted before, I'm missing one 1918 sight variation and the DWM 1914/1920 PS; I have some "extras" : a commercial version, a Mauser made under French supervision, and a couple Navy marked Artys.
I have in total 17 of them.
I have excluded the "contract" pistols, so I have no Persian or Siamese.
I guess one could say I'm kind of deep in the weeds with the L P08s.