I have three Famous buttonholers.
This is an earlier one - it comes with plates that fit both the 27 and 15 machines. I believe the needle plate goes on top of the regular feed dog plate. I know that is how some of the others I have are suppose to work. Ok- I suppose I could go read the directions - but what fun is that?
This one also came with the hole cutter with three knives. And that is part of the original set. I don't have original directions for this one, but I've seen them that show the knife on the parts sheet.
This one is for White Rotary model C. I think the only difference is the feed dog cover plate . . . but since I don't have a VS one, I'm not sure.
I also have one with a plate the fits National rotary machines. It's about the same but with a different cover plate.