Regarding the date, it looks that we are in the 1972-1973 period. See pages of the 73 catalog below. However, none of the references for a Leonidas/Sportex by Heuer matches with your 608602. Nevertheless, if we follow the logic of the references table, a 608602 would be similar to a stopwatch 608601 but for 1/10th sec. instead of 1/5th. Maybe a picture of the stopwatch would help.
Jean-Pierre

: Can anyone tell me when this timepiece was manufactured, I have
: been reading, forums, and understand that Leonidas would add the
: brand Heuer to their timepieces although they were not the same
: manufacturer, the box is blue, and only has Leonidas on it, but
: the guarantee booklet does have both names hyphenated, the watch
: is not my own, I am trying to find out some information on
: behalf of a colleague.
: Thank you for any help you can give me,

: Kind regards,
: John Romer.