I have a feeling that 'Sklo Union' is simply Czech. for 'pressed glass', so in that sense this is Sklo Union - although whether this was made in Czechoslovakia remains to be seen - it may not have been.
Good thought though, and the 'bird bath' base can often mean the piece is from that part of the world - however, the picture of the base I'm seeing in the link from John does not look like the 'bird bath' base on genuine Czech. pieces - with those there is usually a substantial indent.
Driving yourself nuts because a particular design can't be found, is a common occurrence, try not to let it worry you too much - sometimes we just have to learn to live with failure
