The mattress that came with our Pinnacle was not very comfortable. Slept on it for 2 nights for our shakedown trip and bought a Sealy Cocoon from Costco. We have the queen but I didn't measure it. The replacement was listed as 60X80 also and it fit perfectly.
2020 F350 Platinum, srw, lbcc, 4X4, 6.7 diesel, 12,400 GVWR
2020 Pinnacle 32RLTS