Is this Zenith Stellina Cal 601-6 Authentic?

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I may end up buying this watch, with the description provided as above. in my research though I couldn’t find any casebacks without a reference number on the inside, unlike the situation with this one. Any help is appreciated.




 
Posts
80
Likes
139
I'm afraid it's a frankenwatch
Phew, I lost the auction but good to know nonetheless. Thank you.