Eric,

I have a Dane sniper in the original 8x58R.  They were originally made in this caliber and 6.5X58R.  I will do some more research, but I believe that the 45-70 would be an after market change.  Everything else I can see from your photos looks correct, though.  The front sight looks right.  I will have to take a closer look at the rear sight on mine to be sure if yours is original military or not.
It is normal for the barrel to only be marked with the caliber and Otterup.
Let me know if I can be of any other help.  I love these Danes and have quite a few of them.

Best regards,
Tom