This company in Germany sells that steering wheel.
I have installed it in my W124, but in Zebrano.
Here is the website:
If you click on Mercedes, then W126, then steering wheels, you will see they have several steering wheels made in leather and wood that fit your chassis. Unfortunately, that style steering wheel that you see in the picture is not available for your chassis.
The reason is because they take a genuine OEM steering wheel, cut out the top and bottom portions, insert the zebrano or Burl wood in its place, and then re-wrap the side portions of the wheel in leather.
Many of us on the mercedesshop forum have ordered from that company, so they appear to be safe.