To be sure you should call Jayco with your VIN number and they will tell you.
You don't say what year your 264BHW is but most coming off the line today are TPO.
My 2016 27.5 rlts is TPO. If the material is white on both sides it is TPO. Not sure if your trailer has a bathroom fan but if it does just pull off the trim piece (few screws on mine) and it should expose the roofing material where you can see both sides. White/white= tpo, white/black =epdm