Luca, the dagger seems to be a late production HERDER army (at least the crossguard is). Socalled "swirl pattern" scabbards have been produced during the period (late) and have been faked postwars. To me it looks like a period produced one (I think also used by HERDER) with the proper scabbard bands.
The exact ZEITLER mark is shown by TTW in his army book (erroneously ! as distributor mark).
The whole dagger looks homogeneous so to me it seems to be a legit, period produced (rare) ZEITLER army dagger but an in hand inspection for a final statement would be best.

BTW, my personal feeling is that you should at least mention that you have put the same question in another forum.

Regards,


wotan, gd.c-b#105

"Never look for sqare eggs" as a late owner of an original FHH-dagger used to say.