"bisher vermisst" = previously missing
Likely, there are records but I don't know who or where they would be or what information was kept. Does the source where you acquired the records note what additional information can be gleaned and from where?
Regarding, the reference to Seidel - it would simply be a guess on my part - likely, yes to your question but better to post the image so the document can be seen and reviewed.
What does the column or box indicate where the info appears?