The question was asked on the Military Watch Resource forum about when these dials were introduced, and this post expands and clarifies what little I know.
These watches have the "T in a circle", indicating a tritium dial, so introduction cannot be before the early 1960's.
A look at DEF STAN 66-4(PART 4)/Issue 4, Watch, Wrist, Electronic, General Service, issued 29 February 1980 we see the relevant W10 codes. Their relationship is shown in the following diagram, and we can trace "International" back to the Army reference number - W10/VB10028 and down to the interim NATO number with the final numbers that appear on the IWC dial - 445-5890. We can do the same for the other watches: Omega - W10/445-2031, Record - W10/445-9830 and Timor - W10/445-9855. You sometimes see Record watches with the W10/445-9830 dial but I don't have images of either the Omega or Timor.
The number is described as an interim NATO number in the above document and is still listed as interim in DEF STAN 66-4(PART 5)/Issue 3, Watch, Wrist, Electronic, Navigator, Luminous and Non-luminous, issued 19 June 1981, almost 18 months later.
When did they start being "interim" NATO numbers? Earlier documents I have e.g. DEF STAN 66-4(PART 4)/Issue 2, May 1971, don't list the W10 with an interim NATO number. I don't have DEF STAN 66-4(PART 4)/Issue 3 which may clarify the issue.
I suspect these dials were introduced somewhere between the early 1970's and possibly as late as 1980.
Any further insight would be appreciated.
Most of the relevant Ministry of Defence documents mentioned can be found at Def Stan Series 66 - Instruments and Laboratory.
There is a typographical error in the table in DEF STAN 66-4(PART 4)/Issue 4, Watch, Wrist, Electronic, General Service with a "4" missing from "445-5890" but corrected in DEF STAN 66-4(PART 5)/Issue 3, Watch, Wrist, Electronic, Navigator, Luminous and Non-luminous from which the above table was taken.
Cheers from the cellar
A link to: Royal Australian Air Force Watches