Any chance of identifying old stop watch?

I've got an old stopwatch I rescued from work. Google image search would have me believe it's a 70s Sportex / Heuer stopwatch. I personally find it unlikely since I dont see any that don't have numbers on the dial.
I mostly just play with it as kind of a fidget at work, but if it is indeed a Heuer or something with some value I'd likely try to replace it's missing crystal.
Anyone have any insights?