Hi SleepDeprived,
There is only one store listed in the Seattle/Tacoma list in the Kitsap peninsula area so I took a look in an area centered around Bremerton / Silverdale and these are the local stores I would focus on (out of about a dozen stores and chains) and the brands they carry that have the best odds of being able to find out what is in the mattress. All of these have also told me they would call the factory to find out the specs of their mattresses if they didn’t know them.
404 Not Found Silverdale, WA. Pure Latex Bliss (Talalay latex), 45th Street Bedding (Dunlop latex mattresses), and Easy Rest memory foam mattresses. Good people with some good selection and focused on knowledge based selling.
http://www.mattressranch.com/mattress-ranch-locations Port Orchard, Silverdale. Lady Americana.
http://mattressdepotusa.com/mattresses.htm Silverdale, WA. Easy Rest (memory foam), Restonic (latex hybrids), Emerald, Lady Americana.
Phoenix