There will be little in common from one conversion van to the next concerning insulation. One will have to peek to know for sure, and even then a full tear down might reveal that some areas one would expect insulation to have been installed, to be free from it.
Me thinks the workers in conversion companies smoked a lot of crack on their lunchbreak while the boss was locked in his office watching internet porn.
They used drywall screws to hold my fiberglass roof to the sheetmetal, and there were some pockets of pink insulation here or there.
Be sure to get some dust masks if disturbing this pink insulation and if you are sweating, use long sleeve shirts and if you still get the fiberglass itch, cold water shower, not hot.