Just got an email from Keystone, the warranty IS transferable:
Good Morning Paul,
Thank you for contacting Keystone RV. Keystone warranty is one year from the original date of purchase, regardless of how many times it is sold. So to answer your question, yes…it is transferable.
If you have purchased an extended warranty through your selling dealer, you will need to contact them for details.
Thank you,
Sherry Clayton
Retail Coordinator
Ph 1-866-425-4369
Fax 1-866-273-1451