It might not even be a Ulysse Nardin. You would want to see the movement and inside case back. Redial would be reason enough to keep looking.
Vintage (60s and 70s) UN is tricky, and heavily faked. In fact there are probably more fake than legit out there, especially with the script and painted logo like the one above. So at best it is a bad redial, at worst a cheap fake. I bought this one earlier this year here on the forum: UN back then wasn’t nearly as high-end as it is today, and was a few steps below Omega for example, but you can see it was still many steps above the quality of the fakes that saturate the market...