Look at the nameplate. It should say who made it, when, where, what the maximum wattage is, and stipulations on operation and installation (such as if insulation can contact it). It is usually is located on the inside of the can where the lamp sits. You may have to remove the trim ring to see it well enough to read.
If it isn't IC rated then you can build a box over it (with clearances recommended by manuf.) to seal it and then place insulation over it. These boxes usually have to be at least 24" on each side... Do what the manuf. says when building boxes.