I know the 914-4 came with one horn standard mounted on the drivers side and the second horn on the passenger side was optional.

The 914-6 came with two horns standard correct?

I have a few horns, some with rivets holding them together and a couple that are screwed together with a screw and square nut.

Question. What years came with the screws vs the rivets?

Is there a hi and low pitch horn? If so how can you visibly tell the difference?

What is the correct finish of the metal face cover of the horn?

I will post some pictures of the horns I have shortly.

AFAIK the frequency is stamped somewhere on the housing
very small, hard to find - especially when dirty
IIRC the standard horn ist at 440 hertz ...?

Early cars had screwed together horns. Not sure if they were broken down by year model. I pretty sure it the later rivet model replaced the screw one when the supply ran out. Each horn has a hertz stamping on it denoting hi and low.

Looks like I am in need for a pair of early horns !

Hello!

Maybe like to the Karmann Ghia:

http://www.vw-online.co.uk/acatalog/Karman...nn_Ghia_30.html

Niklas