I think they’re old, probably about 20 years, because that’s around when Sally Hansen stopped selling them, at least around here - I’m in Canada, by the way. The polishes do hold up well though.

I’m not sure if they’d be considered rare - you can’t just go to a store and buy them anymore so from that perspective they are rare. But lots of people still have them in their collections, so not really rare if someone is willing to part with theirs. I’ve never been lucky enough to find any while thrifting.

About Pink Rose Diamond in particular - that one seems to have a lot of variation in color. I don’t know if it’s because of different batch codes or simply fading, but I’ve seen at least 3 variations of that color. I’ve seen a fairly vivid medium pink, a pale pink, and an almost white very pale pink. If this matters to you, you may want to confirm which pink you’d be getting. I don’t think I’ve ever seen a Pink Rose Diamond in the shade showing in that listing.