Only Pure Pot Still Jameson I'm aware of is 15 Y.O. Limited Edition Pure Pot Still. My guess would be that 12 Y.O. means there Jameson Gold, but what I have read, it isn't Pure Pot Still whiskey. In fact, to my understanding many Irish Whiskeys claim to be Pure Pot Stills but are not ... too bad, that it isn't such a term like Scotch Whisky and Single Malt from which you know what you get.
P.S. Redbreast, luckily I still have half a bottle left.
Green Spot is on my must-get-list, but Jameson LE PPS is way too expensive for me.