I am not very active on true trophies I am more active on TA but I love me some Sly Cooper
So the legit way to do this is you have to enter the stage with 2 lucky charms or 1 and almost enough coins for another. you need to just tank your way through the first 2 sets of turrets.
Now you will see your first flashlight guard. when he turns around duck to the right and wait for your opportunity to take out that guard.
opposite of where you entered that flashlight guard section there is a bookshelf that comes out of the left wall. jump ontop of that with the stack of books next to it. You will see a naturally spawned lucky charm here and you can jump up to the top floor.
All you have to do now is run through the rest of the level and tank one more hit through a turret carpet and you are good.
I had a bug or something happen though that when I entered the level and left the level to collect some lucky charms for the stratedgy above the trophy unlocked. I do not know exactly how I got that to work but that is what happened.