Vintage Heuer 980.031N has TAG Heuer case back?

I’m looking at a vintage Heuer 980.031N and noticed it has a Heuer dial with 1000 under the Heuer logo, but it has a Tag Heuer case back, as well as a Tag Heuer bracelet. Is this possible? Has anyone seen this before? I know that the dial with 1000 was a later, and possibly the last dial before the Tag merger. Would they have used that dial in a watch with Tag Heuer case back?

I believe the Heuer 980.031L was the last of the Heuer branded 1000 Night Diver watches (aka The Living Daylights Bond watch). The "L" is the version with Heuer and 1000 under the logo. While the "B", "N" and "D" suffixes that followed were branded TAG Heuer. So, a correct 980.031N should be branded TAG Heuer, not Heuer.

I suppose it's possible that the one you saw is a transitional piece with a parts mixture from the factory, but that's not normally the case. Or it might be a franken watch done after the fact.

Thank you for the response. I’m not a watch expert and know almost nothing about the Tag brand, so your response was very helpful. I know if it were my company I would have wanted my new branding on that watch dial. That said, I have seen examples of that sort of thing happening in other industries. My gut tells me the Frankenstein option may be more likely but, again, I have no expertise to back that up.

Thanks again!