Though this rifle may look like a sporterized surplus military rifle, it is not. At the time it was proofed there were no "surplus" M98 rifles, as these were still state of the art military rifles.
The CROWN-crown/N proofmark shows it was civilian proofed according to the rule of July 23, 1893, using the special "4000 atm proof powder". This proof was in use mainly before 1912, though Zella-Mehlis apparently sometimes used up left-over powder up to 1922. IMHO this rifle was proofed before WW1.
In those innocent days around 1900 it was usual practice to include some sporting rifles in the military calibers into each shipment of military rifles to foreign countries. These were meant as "presents" to the decision-making officers. Mauser, Oberndorf sent C-type "Army Hunting Rifles", for example some in 7.65 mm for Argentinia, see Jon Speed's first book "Mauser-OOSR" page 111.
Ludwig Loewe/DWM also had sporters, the so-called "Plezier rifles" built on left over M93 Spanish Mauser actions and shipped them, together with the military M95 7x57 Mausers, to the South African republics Orange Free State and Transvaal, where the sporters were not only used for hunting, but for shooting Brits too. These plezier Mausers are now rare and sought-after collector items. All these rifles show civilian proofmarks.
IMHO this DWM made, civilian proofed sporter served as a present (or bribe) when it was shipped to a South American country. At least, it looks somewhat similar to a Mauser C-type with the military stepped barrel and front sight base. Though DWM did not offer sporters to the public, they made several hundreds at least, but not for sale.