Mauser never made such a contraption, but I believe the GECO outfit in Germany made some military Mausers into shotguns. So did some private gunsmiths. I believe most of these conversions were made after WWI, not WWII, so the receivers should reflect pre-WWII manufacture dates.

These have thereputation of being horrible clunkers, if not actually dangerous - many has the front lugs ground off the bolt, and were locked shut only by the safety lug on the rear of the bolt!

Bolt-action shotguns made for Sears, Monkey EWards, Westrn Auto, and the Savage-Stevens, Marlin, etc., lines aren't built on old Mausers at all, but on actions specifically designed to use shotgun shells. These are safe and effective enogh, but have horrid weight/balance and handling characteristics.