...I thought they were 404 dials that had been amended to read Autavia by someone unscrupulous.

Then we saw more of them, and closer up, enough to see that the quality of the Autavia printing was sufficient to believe that these were ex-factory rather than reprinted. But they were all loose dials, not mounted in a watch.

And having seen a few, more crop up and now they were appearing in watches. Perhaps it was a run of prototype dials that never made it to production and were only now being mounted?

But then David was contacted by the original owner of one from circa 1965 and, bar the incorrect replaced bezel, it was confirmation that it had actually made it to production.

I do wonder if it was in limited markets though. We don't see many, and it never caught on enough to also have the Deci and Pulso dials that typically followed after the Tachy version. My theory would be that it is quite an early Autavia - it's not in 1966 and 1967 catalogues so I figure earlier than that - and that the success of the Carrera, with its own on-dial Tachy, Deci and Pulso scales, killed off this nascent line of scaled Autavias.

I see nothing to suggest it would have been, or was ever intended to be, factory mounted in a Carrera case and the serial number of yours is too late to coincide with the dial features Jasper. There seem to have been considerably more dials produced than were fitted and I feel that indicates an aborted production run, perhaps in a test market or two and lots of surplus dials. And that leads me to believe yours, and any other Carrera cases with this dial, are a marriage rather than as they came from the factory.

Perhaps there is a clue in this 1963 catalogue:

The note at the top that mentions "Dials with special graduations" I always believed applied only to the pre-Carreras and not to the Autavias on the same page. That was certainly the case on later brochures that had the same text alongside Carreras but, at this early stage and having seen quite a few of these dials now, I can see that it might also have meant Autavias. In which case, there could even be Deci and Pulso versions of this dial too. The bottom of that page exhorts us to write away for a detailed chronograph catalogue - the answers could lie in a chrono catalogue from 1963, 64 and/or 1965, so if anyone has one of those, please take a look and see if the watch is shown.