I’m not sure why they’re different. Must probably have been some local law or regulation (Similar to the french taillights), which required different blinkers.
Here is a comparison of three different types.
Left: West germany”. It has a tilted rubber piece, for a more angled turn signal, and a long tail connecting cable.
Center: Original ones that came on my 1972 swiss (european spec) cars, with straight rubber. Unfortunately the cable was cut, so i have no reference here.
Right: Some asian Turn signal reproductions with a short tail cable and different connector and “straight” rubber.
I wish i could find out the reason behind this. An odd and probably rare piece. Nice to have in my collection.
Update: Some users told me that their non-west-germany specificed cars also have the tilted angle rubber, so this might not be the difference.
One reader pointed out that the front turn signals (mounted on the front bumper) also have a “west germany” specification. He guessed that due to the long cable on the side turn signals maybe they were connected together in west german cars?
I have to investigate further whenever i find some time. Interresting details nevertheless..