They will not be using high-temperature heat treatment to cure the paint.
My understanding when it comes to high-temperature heat treatment is that it is used simply to speed up the paint curing process. Given my particular vehicle, I imagine the body shop wouldn't use high-temp heat treatment to cure the paint, instead just letting it cure at a reasonably safe temp regardless of how long it takes for the paint to cure (within reason).
Depending on the catalyst used during the painting process, paint can cure at 65-70 degrees F--it's only a matter of how long it takes to cure at those temperatures. In my local area the ambient daytime temps are/have been in the high-70s so I would think the indoor temps (or at least that of the paint booth) will be just as high if not higher even without the addition of high-temp heat treatment.