Yep, Most of these were chambered for 7x57mm (same as 7mm Mauser). Some were converted to other calibers.
So, as C3 said, get it to a gunsmith and verify before shooting. Saw one of these fail on the gun range when someone fired 7x57 in it. It had been rechambered and the case split in the chamber and blew gas back in the shooter's face and had the bolt locked up pretty tight.