[DonVoigt]

Re-worked/repaired/re-built/re-furbished- yes; by Mauser - No.

Mauser barrels would have some marking on them.

Both barrel and side plate may be of later, commercial, origin. There is no way to figure out when, where, or by whom it was put together as it is today.

Your first comments were right on, you have a mismatched shooter, enjoy it.

Its value is as a shooter, everyone has a different opinion as to "value".