Odds of finding antimagic/combat training potions in ID?

[Parcae2]

I've been playing SVN using the files Graziel posted, but I have yet to find Combat Training. Are they guaranteed by any point? What are the odds they will spawn on any given level?

[darkgod]

They are "low rarity" artifacts

[Parcae2]

They don't see to drop very often. Admittedly I restart characters a lot, but I see Tooth of the Mouth on every character that does more than a couple of dungeon levels, whereas I've seen the AM potion twice and the combat training one once.

[Canderel]

I have a lvl 18 summoner with the Anti-Magic one. I haven't seen the other one yet.

[Parcae2]

Is there a way to check if the item has already dropped? It really sucks to be unsure if you've blown your chance to get one or both in a given game.

[darkgod]

Uniques are preserved in the ID, if it was on a level you left it should be able to regen later