From what I can gather In 1976 the Swiss / Geneva division of Pulsar made these pocket watches. Oldpulsars.com show the prototype designed by Jean Wuischpard with a different finish in gold-fill.
Oldpulsars notes that they where not made in 18k Gold or designed by Andrew Grima. So this is an amazing rare find !
From this Swiss Pulsar advertisement it mentions Andrew Grima. But from the translation it says Pulsar has collaborated with Andrew Grima. So this might be the confusion of him designing this particular model. I'm waiting for information from Andrew Grima wife to see if there was any involvement from Grima in the design. As we can see there are no Grima markings but it has his trademark hammered finish which can be seen on some of his Pulsar Grima LED collection.
The advert shows the Sterling silver Calculator pocket watch, and also a non calculator model which appears to be 18k.
Translation...
" everyone owns a watch that is precise enough. To change watches, one needs a reason that isn't rational, rather emotional. That is why Pulsar has collaborated with the most imaginative designers - notably, Andrew Grima. The results are here: Pulsar veers away from the "watch" to find itself in a completely different universe: the universe of gifts - the gifts close to the Jewel. This enables the watchmaker to touch a completely different client-base" Here are some shots of the actual watch courtesy of the
http://www.theledwatch.com