Dear Derek,
Thanks for your message.
Have not found the exact reference. It happens a stopwatch is not in the online catalogs. However, have found a trackstar with same dial but with one lateral pusher. Its reference is 602.602 and it’s a 602.302 variation. So yours could be the same kind of variation of the one command timer 603.302. The reference could be 603.602 but it is just a supposition.
![](https://ikonicstopwatch.com/wp-content/uploads/2023/04/trackstar.jpg)
Here is the link to the page : https://ikonicstopwatch.com/heuer-leonidas-1978-vintage-catalog-french-edition-iiu-33/
Can not give you more information about the “smith” one. Maybe a rebranded trackstar…
Best regards