What do you mean the 'Halequin Codex'? The only ones that are even close to be legal are the one s from the Journals #39 and 44. If that's what you're saying you're good to go. Except in one other Journal there was some stuff on the Dark Harlequins. The ones that closer resembled their Dark Eldar cousins. I don't have it and I can't remember how many rules were in there but there were alot of cool conversions.