I don't know that there is anything "wrong" with it as it appears to be a Suhl/Zella Saint Blasii example. Any marks/single letters or anything on the lower rib? If Sauer performed a re-barrel, I'd expect to see a "Krupp" stamp of some sort unless cast or other's fluid steel was used. Let me compare the fences.

Kind Regards,

Raimey
rse