Not entirely sure if this answers the headlight question, but I've got it that on 24 March 1950 from chassis number 10 155 020, body number 103 707 the headlights were now from Bosch (formerly from VW). I've a headlamp with both VW (top) and Bosch (bottom) markings on it (the other only has Bosch?), so I'm guessing this may be what you're after.
Hope it helps,
Dan.