If "a crystal is a crystal, is a crystal", then it would hardly seem worth the effort, and the risk, to hunt Krayt dragons, for their pearls, if all you want is a lightsaber. They might make great jewelry, for royalty, and if you need a lightsaber, and are stuck on Tatooine, it might be the only viable option, but later books did reference these as options, and Luke did later try to ban, for lack of a better word, his students from seeking them out, both due to the risk, and because there aren't that many of the creatures; sort of like rhinos, elephants, or other big game, you start to notice that they vanish, as you kill more for a little bit of them, and this hunting was hurting what little Tatooine had for an ecology. He also didn't take this option, himself, either making his own (old stories), or perhaps finding a new one, from somewhere, in Kenobi's home, and he was able to supply his students with more, later in the novels. If the Krayt pearls are no different, no better, then who'd go after something you can only kill with a cinematic fatality, and high explosives, most of the time (you can't just fight it, in KOTOR).
As for "hearing", I'd wonder how close you need to be. People were killing the above mentioned Krayts, hoping for their pearls, but, like oysters, there isn't always a pearl there. A Force adept could probably dodge a lot of sorties with the big lizards, if they could've heard the presence of the pearl. Seems sort of weird, on several fronts, now.