I got mine yesterday also. I didn't have a code when I registered. I was actually a day late according to info on the link (posted here a while back) but the link was still live so I signed up. I will have to wait until Father's Day to find out for sure if the adapter fits the one I will get, but I think so.
I guess I did use a code. I forgot. I actually did it on April 1, even though it said it ended on March 31. I clicked the link, it still came up and still let me register. I figured it was worth a shot. But when it didn't come for a couple of months, I figured I missed out. Then I got a nice surprise in the mailbox the other day.