These are the BOSCH Ignition Kill-Switches https://pbase.com/9146gt/image/40344789 used by the Porsche factory in the 914-6 GT race cars. There are two switches in each car; one is mounted in the cockpit between the two seats while a second switch is installed externally on the cowling just in front of the windshield, driver's side https://pbase.com/9146gt/image/54417622. The turn-key is normally 'removable' in these switches. BOSCH pn: 0 341 001 001

Several years ago I came across a couple of Black BOSCH kill-switches https://pbase.com/9146gt/image/159008290 and what caught my attention and found interesting was the fact that they didn't have the usual 'removable key' https://pbase.com/9146gt/image/159008305 like these do https://pbase.com/9146gt/image/40344792 Other than the obvious color difference and the removal key feature, both switches are exactly the same part.

This is all my own speculation. By the design and overall appearance of this box https://pbase.com/9146gt/image/159008292, the black switch 'may' be an earlier version, possibly a predecessor to the silver switch https://pbase.com/9146gt/image/40344790. Perhaps the black switches were custom spec by another car manufacturer.