AFAIK neither GHS Pressurewounds nor SIT Silencers are ground down roundwounds.
This is correct. They're what's called "rollerwound", where the outer wire goes through a roller to be flattened into an oval shape BEFORE being wound. Half-rounds (or groundwound), on the other hand, are roundwound that's ground down to a smooth surface AFTER being wound. Two different animals with different tonal characteristics.