I don't know that it's a good (or bad) idea to feed rabbits apricot pits, but I believe the whole hoopla over apricot pits has more to do with laetril (sp?) possibly treating and/or curing cancer in humans than with cyanide in the pits harming rabbits or any other species.
Some poor mentally handicapped kid ended up in jail for five years b/c he was selling apricot pits that he believed were keeping his own cancer in remission. (This was in the 1970s if I remember correctly).
His mom started smuggling in apricot pits disguised as almonds when he sickened again, and he got better. Whatever anyone thinks of the story or the cure, he certainly believed in it and last I heard was still living and healthy.
Considering his persecution, I'm of the opinion his home remedy may well have worked (at least for him), but idk. At any rate, it's possible the whole cyanide in many fruit pits/seeds story may have been more of a scare tactic than anything else. But even pharma moguls have to make a living...