Vintage Zenith

Dear Vintage Zenith experts, I have tried (with no success) to get some info with regards to this vintage zenith watch, I found in my father’s safe. It should be from the 70/80s. I know it has been purchased by my grandfather in occasion of my father’s engagement from a renowned jewellery in Italy and my trustworthy watchmaker told me it is an original piece. However, I found no information on the internet.
Any help would be highly appreciated.

355 in the reference number relate to movement calibre 1740