The creepy pool was in the second book. The Home Stone is a concept appearing in every Gor book; basically every city and village has one (except Port Kar; it didn't get one until the sixth book), and it's a symbol (emotional and legal) of citizenship. I'm not sure which clans you mean, unless you're referring to castes (professional associations).Yeah, I don't remember any of that. I have no idea which volumes I read at this point. Or much else about the series. I remember the creepy pool and something about each clan or caravan having a special home stone or something. And, speaking of slaves, I seem to remember Cabot being made a slave and having to change his name.
The Wagon Peoples in the fourth book are organized into clans, though, so that might be what you're thinking of. And yes, Tarl Cabot is enslaved in the sixth book and decides to keep the name he was given after he regains his freedom: Bosk. So one of his identities becomes Bosk of Port Kar, though his close friends and acquaintances still call him "Tarl" or "Cabot."