Can someone help identify this older Stihl sharpener/grinder

[Bishop]

It was made in Germany. I believe the model is KP7739 but Im unable to find any history or specs....can anyone assist? I can provide additional photos if I knew how, thanks!

 

[Bishop]

Another photo.

 

[shorty2000us]

Is the the HOS grinder? The predecessor to the current USG