Good spot and nice buy Andy.

If you've read the earlier responses here, you've seen the suggestion that the seller missed a trick by parting out the watch (if indeed they had the case). The value would have been considerably higher as a complete watch but then, that was to your benefit in buying the dial and movement.

First things first, what would the watch have been when it was assembled (I like to start with an easy one)?

It would have been one of these, the second generation Carrera 1158:

http://www.onthedash.com/Guide/_Chronographs/63.Carrera/e.Automatic_Early/d.Ref_1158/

And specifically most like the earliest example we show on there:

Worth noting that your dial represents a watch that is earlier again than that example, but the details will be the same so it makes a good point of reference. I mentioned in an earlier reply that you have the right hand set - that's a great start, take care of those and don't let any restorer replace them or mess them around too much. In quite a few years of tracking these now, I have never seen a set for sale separately. The missing register needle should be less of a problem, these continued to be used on CHNs going forward unlike the main timekeeping hands, which were replaced by an entirely different design.

Worth noting the Tachy scale on the watch above. There are two Tachy ranges on second gen Carreras, one running 200-50, the other 500-60. And in a variety of colours too. The one you want is white and shows 200-50 - when mounted, the word tachy should be at 3 o'clock.

And now we come to the case. You're looking for one in 18 K gold, with 18 K caseback, and 1158 between the bottom lugs. I don't need to tell you which way is up on the case as you were looking to restore a Chronomatic Breitling! Jeff mentions that it might be difficult to source a case in the correct serial range. In fact, we don't even know what that range is... The example above is 174219 and we have seen another in that range but we would think that a dial that still shows Chronomatic, i.e. before Jack Heuer gave up that name to Willy Breitling, is likely to be lower. It certainly is for steel-cased Chronomatic dials. So I guess the best advice there would be the lower the better. Hallmarks will be on the inside of the caseback but there is an assay mark in a small indent between the pushers. On the subject of pushers, they should be fluted and also in gold.

So a bit of a search ahead, but what will you end up with once complete? Well, a watch with considerable motorsport heritage, as these 1158s were given to Ferrari F1 drivers during the 70s. And wearing it would put you with the likes of Andretti, Regazzoni, Lauda, Villeneuve...

Fortunately, you are not required to wear garish shirts to go with it!!