If you do not scrap that gray spray on fire proofing, you will not get a good mechanical grip on the steel to secure your boxes or condiut. IMO that stuff should be sprayed on after the rough in inspections and coversare installed on all boxes. That way the applicators can cleanup the mess made when a lot of that stuff is knocked down by almost every trade as the install thier work. This is a continuing problem. Ask the inspector which code you are to not comply with. The requirements for securly installed electrical work or scrapes in badly scheduled work.
