Button replacement

I just baught some replacement buttons from MPC stuff.com. Question, are the buttons for the "undo" function and the "Shift" function relatively interchangeable? They look to have the same dimensions. I am looking for a new program/undo button and they sent me a new "shift" button. I can deal with an undo button that isnt clear, as long as it works the same. Thank you

I haven't had mine open in a while but I'm almost positive they are they same save for the mode one being clear.

http://www.youtube.com/watch?feature=pl ... YqySGH-7k#!

Towards the end the video there's a pretty decent shot on the buttons with the lid off.