According to Andy Strickland or the Cam & Strick Podcast, there were no contracts in place when the deal was completed. According to Strickland there have also been very little constructive contract talk since the deal was completed.
No extension in the original deal is understandable as it likely would have decreased the value received via trade. One other element to watch is the Panthers have announced an introductory press conference, while the Flames have not.