Yes, draft rule that made it possible for teams to protect skater was the deal to make sure the Oilers could keep Gretzky, there was more explicit one for the legends to not have to go back with their ex-nhl teams they hated (Hull-Howe were not protected, but the league accepted to not void their contract I think)
Edmonton has exercised its priority picks by protecting goalies Dave Dryden and Ed Mio and skaters Wayne Gretzky and Bengt-Ake Gustafsson. The Oilers also have made deals with Los Angeles to keep Blair MacDonald in Edmonton as well as with Philadelphia Flyers for the rights to protect Ron Chipperfield.
So maybe, the contract was irrelevant, Rockies having first draft pick was irrelevant and even Gretzky was irrelevant, maybe without him there still a protection system for 4 player per team... and all the talk around this has been non-sensical, it is hard to imagine an expansion of the sorts with just zero protection mechanism and once you have one, obviously it will be used for Gretzky by the Oilers.
It could easily have been all empty talk and just hockey-conspiration drama...