If you have possession of the trailer you can look at the windows and see double vs single pane (thickness) and there would be a label near the door stating thermal package. Not sure what year trailer you have but guessing 2008 which would have enclosed & heated underbelly but, no tank heaters and likely single pane windows as I think Jayco saved those for Designer and Pinnacle lines.
2014 Eagle Premier 331RETS
2016 Silverado 3500 DuraMax/Allison
1975 Corvette & a couple ATV's