What years "DEFROST" script on red heater knobs btwn seats?

[Jdub]

Sorry if this is well known I lack a good hit on my search queries.

Roughly, what years were the plastic red heater controls between the seats inscribed with DEFROST in all caps?

Waxing on this, they must have arrived on English export only? Again, apologies if this already well threaded or I should head to the VW forums

[EC900]

Up to about 1981.
Seen some ‘81 RoW red levers that were blank.
I know Porsche would use up remaining old stock before transitioning to new parts and add a new suffix to the part number. Then came the new universal hieroglyphics style - probably a cost savings measure.

[Jdub]

The move to a glyph makes complete sense - I wondered if the U.S. DOT insisted that the function be named and in English at that.

Thanks for the response appreciate it!