Its difficult to tell what's stamped on the back of the movement, but this is what I could see, Original klieninger, made in Germany jewels unadjusted 83k 26,9 100 cm jak
I found a supplier who has Kieninger pendulums. The pendulum has a 10.5" disc and is 42-1/2" long but it is for a 116cm movement. Can you check to see if the numbers on the back might be 116cm rather than 100cm. If it is you can call Black Forest at 1-800-824-0900. The order number is KPL116-270 They will be happy to answer any questions you have.