Suggest you send an email to AS at JC, Ohio. State your complete VIN, and ask for a mattress schematic to be emailed to you. Voila!
We had a mattress made to Schematic spec by one of the Forum's advertisers - all radii perfect, the price was right, and a much better sleeper than the 10 yr old original equipment.
BTW, this works for electrical, plumbing, and other obscure construction details. Still excellent service after the sale.
Thanks, AS Mgmt, Thor, et al at Johnson City. Much appreciated. Wally would be proud of you.