There may be a tag on your mattresses to tell you who manufactured them. If you're concerned about resale and you want replace them completely, that would be my first choice.
Most Roo owners will add a memory foam pad to the stock mattresses anyway so you might consider just going with an extra thick foam pad on top of the mattresses.
2011 Rockwood Signature Ultra Lite 8293SS, 12K Equal-i-zer
2016 Ford F-250 XLT SuperCrew, 6.2L, 4x4, 6'9" bed, 3.73
2010 Rockwood Roo 23SS (2012 - 2014)
2009 Ford F-150 XLT SuperCrew, 5.4L, 4x4, 5'6" bed (2012 - 2016)