I have one of these and I'm about 90% they're German, probably 50s-70s, but I don't know which company. We had a thread on mine before, but it wasn't recognized as Czech by Jindrich, which makes me convinced even more. I only know they turn up regularly on the German ebay site, usually in green or blue. Someone there seems to think they're 1930s Haida, but I'm very doubtful of that attribution.
Astrid