It's all one piece
It's all one piece, so in that sense it's easy enough, but if you try this particular repair on your own, the "catch" is that the MBP is basically built upside down. The top case is the primary component that everything else is built around. So you basically have to completely disassemble the thing and then rebuild it inside the new case. It's a PITA, and if you don't have some means of aligning the display assy hinges, it can be made that much more difficult.
So this is a good repair to take to an AASP. I say AASP, because Apple likes to kick its repair network "partners" in the teeth on a regular basis. Saying how they aren't allowed to do this or that, which seems designed to frustrate customers who will then take it to an Apple store where they'll be told something along the lines of, "I don't know what their problem is, but we'll take care of it for you!" And of course AASPs are gagged from saying anything under threat of losing the ASP contract. So at the same time Apple is kicking them in the teeth they're eating their lunch, which is why I'd recommend throwing a little business their way whenever possible.