MY "first thought", to ask what you're planning/hoping to achieve by the ID. That likely telling how "generic versus specifically you need an ID.

There are 'other means 'other than' photo ID and experts to "possibly" ID, at least categorically. The positive, a lot of good information on the Web. Reference one such source at the Website referenced below. Essentially a "line up" with "mug shots"! Quite a few mausers there!

The bad news... A. requires some expertise to use this site. Inferences going in to assist and inferences as 'best guess' possibly achieved, typically not absolute specifics. The fact that for a totally scrubbed mauser action, usually, extrinsic evidence, such as original barrel - even if simply configuration - as well as any stock information gleaned as 'remnant of original yet available.

It's not unusual for a military mauser action to be scrubbed. What is unusual, a military action yet with original barrel, the whole 'kaboodle' to be absolutely scrubbed. 'Obtuse' barrel markings can sometimes provide pivotal clues.

Last shoe. With up to well over a century for the wide genre 98 mausers to be in existence, likely more 'mix & match', builds, rebuilds, re-rebuilds., further mix & match... Get the picture? What even experts view, they realize typically "indicia" of what the action may have been.

Have a look in the 'do it yourself' ID context... http://www.hoosiergunworks.com/catalog/mauser_reference.html

Good luck!
Best!
John