500 SL Euro Question

500 SL owners and other knowledgeable people:

I have an 82 500 SL. I am having trouble determining whether I have a speedo cable or electronic pickup. On the back of the cluster, there is not a threaded piece to screw a cable onto. It is just a small, white bowl-like piece with a metal rod in the center.

Yet, I found the remains of a detached speedo cable behind the dash! What's going on here? Did someone destroy the speedo cable (it is torn in half) and replace the speedo with one from a later model?

Surprisingly, the speedo functions but reads quite a bit too fast. I am baffled. Any thoughts?

Not sure where to post. Also will post in Tech Help.

Rich Mayer
82 500 SL