Zenith Defy Automatic franken?

I picked this up from ebay for a good price or so I thought (30 day return option so not a worry) and have been trying to identify it but without much success. I'd like to fix it up if possible, but am worried that it won't be realistic to do so if the case and movement are non-compatible. Any help would be much appreciated. This is my first foray into the world of Zenith so I'm a bit lost in the woods.

Here are some images of my watch. What I know, and knew when I purchased it, is that the case back and crown are wrong. The crown stem is a little wiggly, and while it pulls out to two positions, nothing happened at the fully pulled out position. I haven't tried hacking but am told that works for changing the date. It was set correctly when it arrived and is losing about a minute a day so certainly needs a service.

Here are some images of my watch.


It looks like the screws that hold the movement in place are missing, I expect this is an easy fix.

The main issue is that I cannot see any models on an image search like this. Any "C" case Zenith I see is either not a Defy, or has the date between 4 and 5.

So what am I missing here? Any ideas and advice most welcome.

Nick

What’s the issue with the caseback?

It's from another watch!

Thank you - yes, thats the dial isn't it. I will need to have a think about this. I'll see if finding a suitable donor case is a realistic proposition. As I said, the watch was pretty cheap so it could be a worthwhile project - or it could be a mad idea. I'll sleep on it.

another zenith watch or something else?

Don’t know. I started another thread today in the hope of finding out.https://omegaforums.net/threads/identifying-a-case-back.148434/

definitely not a Zenith case. I was thinking it was just the wrong case but a zenith one.

I don’t think the back is for the case. It screws in ok but it looks wrong, it seems slightly too small.