The form I sent in for my Sandpiper had $250 printed on it as well. Took them almost 6 weeks to cash the check and send me the signed form back. I guess the winter shutdown played a part in that.
I heard back from dealer. They confirmed the Sierra is $250 and the warranty will be in effect as soon as the dealer sends in the product registration form. That will be sent once I take delivery. Thanks to the forum for helping this happen and it looks like this thread has helped other members! Great collaborative effort!