I was somewhat surprised on rereading through the first Mistborn trilogy to find, in reference to Spook's given name of Lestibournes:
Lestibournes. Lefting I'm born.
Street slang for "I've been abandoned."
I hadn't remembered this at all (despite remembering the scene it's in), so I'm not sure what else I missed. I know Lestibournes is the name he gave Clubs when Clubs "bought" and rescued him from the plantation and took him to Luthadel. I know Spook is the name Kelsier gave him, ostensibly because he found Lestibournes too hard to say (or maybe because Kelsier knew exactly what his chosen name meant), and Spook stuck with that nickname for the most part after that.
Are there any references at all to his original name, the one he left behind? Failing that, is there any word from the author?