RandArt light sources?

[hyperdex]

I've taken to playing with randarts (4.2.3) and like it a lot! I've had two characters advance to the point where I could accumulate a reasonable number of artifacts, and in both cases I generated randart torches and an Arkenstone. (Both Arkenstones were relatively early in the game, one when I was DL10 and the other DL20 or so.) In neither game did I get a Phial or a Star. (In one of the games I YASDed to Morgoth so I saw a lot of artifacts.)

This leads to two related questions...

In randart games, are we still guaranteed to have Phials, Stars, and Akenstone artifact light sources (in addition to possible lanterns and torches)?

If so, are the level requirements tweaked so that they don't necessarily occur when you would expect them?