The watch the OP linked to is not a Dubois-Depraz module on an ETA movement - it's a Valjoux 7750. There's an easy way to tell:
The pushers for the DD chronograph module sit on a different plane than the crown since the module is on top of the movement.
The pushers for the Valjoux 7750 (and most integrated chronographs) are in line with the crown.
Some Speedmaster Reduced autos like the 3510 use the module. You can see the different plane the pushers line up on over top the level of the crown:
However, the watch in the eBay listing has the pushers and crown in line:
There are other hints that it's a 7750, like the date window and the subdial layout. While not cheap or particularly easy to service, 7750 parts are readily available.
Click to expand...