Not surprised that MB did not have a special holder for the trouble light. These were sold by Bosch and others as an inexpensive (about $2) accessory. Came in a small box or stapled to a card.
If MB did not give you one, you went down to the corner petrol station, or Sears Roebuck (do you remember that name?) and bought one.
They were carelessly tossed into the trunk or glovebox waiting for an emergency. Most were eventually tossed out...and that's why they sell today for a lot more than $2.
Richard M