It was completely different. Nahab was a cult in Shadizar (the adventure was originally written to be in the Shadizar - City of Wickedness boxed set, but was rejected as requiring too advanced of a GM). I later rewrote the adventure and submitted it as a stand alone Shadizar adventure but was rejected on the same grounds. The adventure was then given to Eric for a rewrite. He gave it the title it now has (it was originally called the Dark Bordello, or something like that) and did a fantastic job of rewriting it.
Then it was rejected again for the same reasons (a lot of my adventures seem to get rejected on those grounds). Mongoose then decided to have it rewritten in-house. Although the title was retained, Nahab was changed from a Shadizar cult name to a Corinthian village name, and the resulting adventure (aside from the title) has absolutely nothing to do with what Eric and I wrote.
All that aside, I have a copy of the published adventure and it seems like it could be a lot of fun to play. Written by Bryan Steele, it reads well and I recommend it.