In the 1930s, Portugal was looking to update its small arms, and wanted to get some top-shelf K98k Mausers to replace its 1904 Mauser-Vergueiros. The country was on good terms with Germany, and so Portugal placed an order for 100,000 K98k rifles in 7.92mm Mauser caliber from Mauser Oberndorf in 1937. The first 50,000 (designated m/937) were to be standard production just like the Wehrmacht used, and the other 50,000 (designated m/937A) were to include a few changes to elements like the front sight and sling swivels. All would have a Portuguese crest on the receiver and a 1937 date (although delivery trailed over into 1938), but all of the proof marks were standard Wehrmacht pattern.
These guns were all delivered, and Portugal was quite happy with them. A second contract for another 50,000 was placed in 1941, once again for the standard Germany military configuration. These were designated m/937B, and we are looking at one of those rifles today. In total, 60,000 were made, as 10,000 were requisitioned for German military use. The Portuguese Mausers are a neat time capsule because they show the standard of prewar and early-war Mauser production, and many survive in excellent condition since they sat essentially unused in Portugal instead of seeing combat.
It is worth mentioning that the roughly 10,000 examples seized by the German military have turned up basically everywhere Mausers went, including Russian captures and Norwegian F1 conversions.