Well, the bottom of my pot says Lustre, BUT.....My Indulgence: 7 Palette lists it as a Frost. It definitely has a frost-like texture in the palette (not the chunky lustre texture). So.....I think it has been released as both. I thought it was always released as a lustre in the pot though????
I think that Greensmoke was originally introduced before MAC launched their Lustre eyeshadows. So, it was first called a frost, then when Lustres came out, it fit into that category instead.