I took a closer look at the description .. yes you are right there is a removable back square on the one pictured.
Mine does not have that attachment and never did. When I bought mine a year ago there was no such attachment.
edit:
I watched ceicio7's vid and for the life of me I cannot understand why he has added a back square piece. It would interrupt the image circle.
I've used my FD/m43 adapter with maybe 12 or 13 FD lenses and a GH1 with no problem or need for a square piece on the back.
Have a look at this link http://vimeo.com/user680743/videos
Rooftop Thief, Curtains, Staring at the Sun and He's Up, He's Gone were all shot with this adapter on GH1 and
various FD lenses 24/1.4, 28/3.5, 50/1.4, 35-70/3.5, 24/2.8
also there is a whole bunch of tests using this adapter with a FD 50/1.2 here (scroll down) http://www.dvxuser.com/V6/showthread.php?t=179874&page=3