"Erma's KGP series uses identical mags for 7.65 Browning and 9mm Kurz. This setup works with both case diameters, so a modified mag may not be necessary."
Correct, but what Ed asked about was a .30 LUGER vs the new .30 round.
The case size of the luger rounds are quite a bit different in diameter than the .32 acp or .380 rounds you mention in their European nomenclature.
They will pop right out of a luger magazine!