I just went and looked on the can, and there is no mention whatsoever about heat durability. You might try contacting SW directly and asking somebody that question.
I do have a spray can of plain ol' Zinc Chromate, and it does say heat resistant to 250 degrees. Don't know if 988 is similar or not, but I'm guessing that resistance to heat is beyond its' design purpose.
Jeff
-8 wings