Back in the late '80s I got to visit Modern Props. They were the prop house that rented props for that movie I got to see that prop as well as the Genesis lab computers and other genesis equipment, the STII tricorder, as well as the STII spatula communicator.
The casing was a found item and described as a "jogging computer" by a former Modern Props employee but I can't say if that was the original makers name for the item. It calculated miles run, duration of the run and calories burned or something like that. The top surface was smoked plex backlit with L.E.D.s effects. I can't say how much altering of the original piece there was as I have no idea what it originally looked like.
Jogging really started to take off towards the later part of the '70s and WOK was released in '82 if I'm not mistaken. I suppose looking on Ebay for a vintage jogging item like that would be in order.