I think I have one like the one you are showing or very similar. I bought it in original packaging a couple several years ago in Essen. I though I would install it in my Pagoda. It was packed in a consumer packaging for shelf to be sold as accessory. On the package, among other cars, 280SL was listed (could have been the 107 280SL as well). It might have been coming from 70s or 80s. I remember we had some difficulties wiring it, but anyway I decided to buy HIrschman, so I have this one somewhere...
Again - it was like you would go to a shop and bought a generic antenna - like someone wrote - a consumable.