It may be that the rifle is exactly as it was when it left official service.....or not.
As modifications and upgrades were introduced, rifles would have been "repaired" at anything from the unit level, all the way to "factory" rebuild. If the barrel has been replaced OFFICIALLY, it will bear the appropriate numbers and inspection marks. Official repairs and upgrades are a significant part of the "story" of the rifle.
If the parts are appropriate for the period and there are markings to indicate work carried out officially at workshops or factories, everything will be fine.
If your 1915 rifle survived World War 1 "untouched", it would have been a minor miracle. If it stayed in "the System" after that war, it would have been subjected to periodic 'upgrades" for as long as it stayed in the military system.
If it were sent to some distant colonial outpost, perhaps things may have been different, but not greatly.
The "flat" cocking piece was a First World War "temporary relaxation", because the nice, rounded one took more time, tools and gauges to make. The early one was rounded to reduce damage to the soldiers hand during "bayonet fighting". The "flat" one doesn't seem to have caused soldiers too much trouble; the basic idea went on into the No4 and No5 series without much change.
Enjoy it as a piece of military and engineering history.
And remember:
"Frokost uden Snaps, er morgenmad"
Or, something like that....... (That is about all the DanishI know)