Zenit-1 with addon button?

(well, it has been a while since last time here...)
I am about buying a Zenit-1. I have the Zenit-3 and the Zenit-S, and interested to compare. Unless you have time to search on Avito while in Russia, they otherwise sell relatively expensive online outside RU. I spotted one cheap (no, not on Ebay), from a seller who has not much clues about.
The strange thing is an additional button/rod:


http://www.ussrphoto.com/UserContent2/482019_Zenit-1-mod.png



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Current working cameras:
RF: Fed-2, Kiev-4a. Zorki-4
MF: Salyut, Zenit-80. Salyut-S, Kiev-6S, Kiev-60
SLR: Zenit-V

Hello fotolubitel

I think is a connector for a flash light. Such modifications are not very rare on Zorki-1 or Zorki-3 and others. Here some examples:

https://www.g-st.ch/privat/kameras/bilder/zorki/00021570.jpg

Best wishes - Guido

Thank you Guido!
indeed, it looks absolutely like a flash PC connector core. Just because it's on the top plate I didn't think of this, but was instead wondering about some mechanical addon....
In fact first time I heard about custom DIY flash connectors on these cameras. Thanks for the link.

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Current working cameras:
RF: Fed-2, Kiev-2. Zorki-4, Fed-4
MF: Salyut, Zenit-80. Salyut-S, Kiev-6S, Kiev-60, Moskva-5
SLR: Zenit-V, Zenit-3, Zenit-3M, Zenit-122, Start