At the purchase, no lids were mounted on the car.
They have been found from the supplier JanJack Daniel, but without knobs.

 The refabrication has been done by preparing, first, a sample taking a normal oval knob and adding the “flame”: the material employed for the flame was metallic stucco properly modelled.
Then a manufacturer has made the knobs in brass material from a mould, fabricated starting from the sample.