Very good question!
Basically, the lower (in my opinion slightly earlier) one seems to have no foresight yet.
I agree with you that these differences are very minor and more or less academic. All in all we may attribute a probable dating range of "ca. 1480-1500" to both of them, including the Vienna sample, with a higher probablity towards 1500 for all.
In contrast, the Copenhagen piece clearly features an older barrel with shifted planes in the rear section and a pronouncedly swamped muzzle head (ca. 1470-80) that has been restocked in what is most probably the second decade of the 16th century.
Michael