I wrote to the Målerås glassworks to ask re this plate, and have just had a very helpful response:
The plates were designed by Mats Jonasson in 1981 and were retired from production some ten years ago.
There were four different platters; called ”Carpenters”, “Blacksmiths”, “Musicians” and “Glass-blowers”. They were part of the regular production, not limited editions.
Given this it's surprising I've not seen more about - of course now we'll be awash with them !
Gareth