I came across this Defy online: Has anyone seen a Defy like this before? No shots of the back, unfortunately.
Yes, this is reference 01-0020-380 from 1974, with (presumably) a 2572pc inside. Here is another one from the internet: Zenith Defy 01.0020.380 Veritas99 might even have a catalog shot to share...
Sorry, back to work today and haven't been able to get to the important things like surfing the watch forums. To make up for the delay, here's a catalog shot of the watch along with the corresponding price list from January 1975:
We had a spike in traffic today as people have gotten back to work, realised how dull it is, and decided to look at watches instead. Our traffic follows the work-week closely, monday morning around 10AM USA time is usually when we have you all on here, but new years delayed that a bit