Amateur DIYer and first time poster here. Hi everyone! I was going to replace the cartridge on this Moen shower valve (Legend model) but after I removed the handle I discovered this unusual black plastic housing (mounting adapter) which I want to remove so I can get the cartridge out but I was hesitant because I did not want to break it and then be in bigger trouble. There are no screws on the outside of the chrome hubcap (escutcheon) housing that I can see. But I think (maybe) this black plastic mounting adapter might be screwed onto the valve behind the chrome escutcheon which would mean removing the nice caulking job taking the “hubcap” off and getting inside to unscrew it (hope I don’t need to). This assembly is about 20 years old. Obviously, I want to remove the old cartridge so I can replace it. I have the replacement cartridge (Moen 1225) I just need to know how to proceed to get the old one out without damaging anything. It’s just the darn black plastic extension is in the way. Any help would be greatly appreciated.