i went and had a close look at the horn on mine to compare to OP's posted photo.
and now i am laughing.
another one of those great 914 mysteries.
'cause the horn changed along the way with model years?
so i have a 74.
and the horn is
identical to this.
(except the black paint is flaking on the front surface of mine).
and its original to the car.
and i have had the car a long long long time.
(and its the same horn that was on my 73 VW squareback).
Click to view attachment but - in the past i have always found the workshop manual an interesting reference.
here is the photo in there.
Click to view attachment going by the usual logic in the workshop manual a great many of the photos illustrate early cars and early parts - they only update a photo when there was a major change.
so i am guessing (reasonably i think) thats a photo in the w m of an early car horn.
probably a 70?
'cause then there is a photo of the update horn location in 75 due to collision bumpers.
and
different again.
actually looks like it might have been silverish? galvanised? or silver plated?
Click to view attachment you got to laugh. you never want to ask these harmless questions about what a particular part was ...... ha
but given dennis V is doing a 6 its going to be an early horn.
looks like the horn in his posted photo almost matches the factory workshop horn photo.
though his has a nut on the front the f w m photo does not seem to show (but they did airbrush treat a lot of the original photography in the factory manual illustrations).
but you can see it does not have the perforated hole grille in middle like the 74.
factory manual photo shows the rear body is definitely all black and probably black gloss.
but definitely the central plate is something else. its a black and white photo so not much more info.
but pretty sure they were all VW horns fitted to both the 4 and 6s so its going to be whatever VW were using on all their models in 1970 and 1971.
there is bound to be some VW beetle geek site that lists the horns for every year.
the info will be there on precisely what it would have been originally for the particular type of horn he has for his 6. google is your friend.
......and there is always the chance there were multiple suppliers of a similar product in any one model year!
cheers. still laughing. 914s!!!!! the answer is never straight forward.