R values are often used in the marketing of air mattresses or thin foam pads used by backpackers.   The Rev Tent features a 4 inch foam mattress with dual density layers of foam.  There’s no real reason to test for R-value because it is so thick.  If we had it tested it would probably be in the upper single digits, if not lower double digits -- Much "warmer" (more resistant to transfer the cold from the ground)  than your average camp sleeping mattress.