There is a little bit of mixed information going on here.. so I'll try to clear things up.

As the dial doesn't match the caseback, we are dealing with several scenarios.
The dial & case could be original, with a replacement case back, the case & case back my be original, with new dial - and several other iterations.

Johan, you say that quartz hands won't fit an automatic - this is wrong.
Early 980.006 & it's variants - it's hands will fit an automatic. Also see Jarls comment about which movement to fit.
Secondly, you said the caseback won't fit over an auto movement - this too is incorrect, I have fitted an auto to a quartz before - straight fit, no problem... now this is where is gets confusing...

The later big Heuer divers, that had '1000' written on the dial under the shield.. these had slightly slimmer cases, you can tell these as the bezel actually recesses into the case a little. I can't tell from the OP's photo as it is too much of a 'top down' shot. Anyway, these thinner '1000 on the dial' models had a different thinner quartz movement.. and I am guessing that it might also have a different movement, maybe thinner in the auto models.. which brings us back to there being a problem with fitting an early auto movement to the later thinner model.. which is what Johan might have been referencing.

To really clear this up - the OP needs to supply some photographs of the case from a more side-on angle - then we can determine which case it is - which is key to knowing which movement it should have in it, regardless of the dial.

Stewart
- Heuerville.