We did with our first adoption attempt. We registered and had our baby shower before our bmom changed her mind.

But, I still would have done it that way. It is so joyful to build your nursery from the ground up and when I was doing that I was so hopeful. I would sit in there and rock and just dream. Those moments are precious to me even though our plans didn't work out for us at that time.
Our plans did work out though and we did still have the nursery! And actually, I'm still using the crib and everything!
Have fun. Registering is fun. Decorating is fun. It is a wonderful way to spend the waiting time.

~M