Before I got Basser's comment, I sent Robert Klaas in Germany a message with a picture of my knife. It took a while, but here is their response...
First I have to apologize for our late reply.
Yes, you are the owner of an original Klaas pocket knife.
We estimate the age of the knife of approx 80 years. The marking of the storks has been changed in the course of the decades.
It is not possible to tell you an exact construction year because the knives were made over a longer period. Keep the knife in good condition!
Mit freundlichen Grüßen aus der Klingenstadt Solingen
Best regards from Solingen - the city of blades
Robert Klaas GmbH & Co. KG
Telefon: +49 212 331031
Telefax: +49 212 329560