Nice catch,
I owned this one, but sold it last year. This one was mine, I made this picture:

I made a manual for the buyer, I think it might come in handy for you as its pretty unusual:
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Setting date;
First pusher on the side of the watch in ‘adj/chrno’ mode à set date by
pushing two numbers on the calculator panel, for example ‘25’ = 25th à push
the button on the calculator panel with ‘DT’ beside it and hold it for a few
seconds until the display returns to the time mode. You will now see the
right date on the left.
Setting time AM;
First pusher on the side of the watch in ‘adj/chrno’ mode à set time by
pushing four numbers on the calculator panel, for example ‘0236’ = 02:36 à
push the button on the calculator panel with ‘HR’ beside it and hold it for
a few seconds until the display returns to the time mode. You will now see
the right time set in AM time
Setting time PM;
First pusher on the side of the watch in ‘adj/chrno’ mode à set time by
pushing four numbers on the calculator panel, for example ‘0236’ = 02:36 à
push the button with ‘PM beside it (you will see a dot appear above pm) à
push the button on the calculator panel with ‘HR’ beside it and hold it for
a few seconds until the display returns to the time mode. You will now see
the right time set in PM time
Quickset seconds to 0;
Push the button with ‘sec’ beside it. Pushed when seconds are below 30
seconds it will reset to 0 on current minute. Pushed when seconds are past
30 seconds it will reset to 0 on next minute.
Setting alarm;
Like setting time , but push the button with ‘mrc/alm’ beside it to set the
alarm time
Toggle alarm On/Off ;
Push the button with ‘mrc/alm’ beside it
Beep when pushing buttons ON/OFF:
Push the button with ‘key/calc’ beside it to toggle On or Off
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Goodluck, and enjoy the use!