things are going a little bit over and under.........
the series i am looking for, and in this series only for the model Mm410, as shown in my pic.
Here's thread from another 'site, six years ago, with the same question you have (and several photos of such bolt). Scroll to post #5: K98k Forum
The rifle in that post is identified as S/N 45625, only 582 after yours.
An answer (from a moderator of said 'site) posted as being forwarded from Jon Speed (author of Mauser Smallbores):
Conveying Herr Speed's remarks: "This Plunger unit appears to simply affect directly the firing pin movement as bolt is opened and closed. Its function is a little like the lock plunger on a 98 bolt sleeve unit from a mechanical point only. Its a Plunger activated by contact with parts of the system as the bolt rotates ! It would appear at thiis late stage 1933/34 that the Mauser folks were trying out one last concept for this generation that would soon phase out as the B series came on line."
-------------------- Citizen of the Cherokee Nation