Basically all I can say is that she was presented at birth ( shortly after) branded which simply means she as papers. She would have had to be presented later to get the neck brand. Now I am not totally familiar with the branding procedures beyond the hip branding but the neck brand would have her year of birth and a few numbers from her UELN. This number ( the UELN) is traceable.
IF she came from Germany then you will have to contact the German Society.
IF however she was actually foaled in NA ( and this is a very real possibility) then you would have to contact the AHS.
The closest line she looks like is the "G" line of which many looked a little coarse back then.
Just a note...if the ranch branded her on the neck as many ranches do then you will have a tough time finding out anything about her.