Pre-WW2 Mauser calibres

I was looking at Mausers for sale on some online stores and noticed a number of Mausers described as:

"Oberndorf Mauser Commercial Sporting Rifle Type B manufactured 1920-1921" in 30-06 calibre.

Are these Mausers authentic or after market custom works?

I'm skeptical because I didn't think the Germans manufactured their rifles chambered in an American calibre cartridge especially pre WW2.

Nothing factual or anything, but Mauser Oberndorf being a private for-profit business, I suspect they would make a customer a rifle in any caliber requested, as long as you could pay the price. At the same time, a given rifle could have been rechambered or a new barrel installed at any point in its life.

Comments from Bob T:

Paul: You may have noticed the k98k forum question about the Oberndorf sporter in .30-06. Mauser made sporters in this caliber before ww.2, as well as before ww.1. They had pretty good sales over here even then and could sell ought sixes to the Americans. .250 Savage was another relatively popular caliber; they used it in their kurz action sporters. The .250 apparently had a pretty good following in Germany, which the ought six didn’t.

Thank you gents. I never thought about the capitalist side of German arms manufacturing.