Mark,
since I've many watches of the period, the Heuers but also a 1955 Breitling 806 Aopa, a 1961 Speedmaster 2993-3 Lollipop,
i'm buying a dosimeter/geiger and then we'll have the definitive answer!

: Hi Paolo.

: There's ben discussion about the lume on these early Autavias
: before. Personally, I doubt it is radium - that was already well
: on the way out as a lume material for everything except
: applications where the strongest self-luminosity is needed, as
: in some military applications where radium use was permitted for
: far longer than in civilian watches. At the time, legislation
: was also moving towards the requirement to mark for tritium and
: I think it far more likely that these earliest Autavias are
: simply unmarked tritium than radium.

: Great watch whatever the lume material - these large register
: Autavias are some of my favourites!