Bogus found his green stone armor on an undead troll weak enough to be defeted by Bogus. It was never confirmed that it was enchanted at all. He was quite satisfied with the armor though, but a bit worried that he could not sleep in it. Perhaps it should increase MR vs sleep spells
Precious was bought from an old and wizened reptilian alchemist and trader of enchanted paraphernalia. It did cost the greater part of Bogus' collected gold stash, but it turned out not to be very powerful either. Still it was precious to him.
BTW, you are not supposed to take Bogus' things from him. Especially if you think that you can make better stuff for yourself.