From other postings I have seen, the license is not an exclusive one. So both are doing the setting. Pinnacle originally announced that Lankhmar back at Gencon'14. That announcement was part of a broader "here are the things we are comfortable telling you we are working on that will be out in the next year or two" (In the past Pinnacle never announced anything until they were just about ready to release or launch the Kickstarter). Below is a link to the flyer from GenCon.
Coming VERY soon...Savage Lankhmar: City of Thieves!
Our favorite Setting Rule:
No Honor Among Thieves
Betrayal is a part of life in the City of Thieves. Sometimes a companion double-crosses his mates over a few gold pieces. Other times he might cheat on a friend over the love of a woman. Most of these betrayals are met with a wry smile and a vow to reciprocate at some future date. There is no honor among thieves, after all.
Sometimes the betrayal is more personal. In Lankhmar, whenever a character is betrayed by a close friend or associate (a trusted ally or even another player character—Game Master's call), he cannot spend a Benny to reroll any opposed defensive action.
If the betrayal is an actual attack (almost assuredly with The Drop) and the victim doesn't Soak all the wounds and / or remove the Shaken, he must make a Vigor roll versus the damage or go unconsciousness per the Knock Out Blow rules on page 25). He may not spend Bennies on this roll.