These marbles were made in the 1920's in Portugal by one glass family factory from Lissbon, they are very hard to find, even here in Europe (I'm from the Netherlands) and they are a lot rarer than German handmades. Some of them are very beautiful. They were never exported outside Europe, so that's why you do not find them in the US.
Most of them are left twist, and the pontils are made in a different way than the German ones.