1st off Herder was a tiny maker and bought all their parts from other guys so I have no idea how to positively say this is Herder. But hey I'm learning too.
The pommel is very distinctive. Look at how it's turned right into the underside. Klaas used these but so did other makers. Similar one can be seen in Witty's reference pg 136.
If you can show the top of the crossguard I could possibly tell the crossguard maker.
The scabbard is generic.