@Otis- I agree with you but the only exception I have is over the years my barrel or one of my friends got away on us and ran way high in temp. I would expect that if the heat was high enough to discolor the outside paint then it was pretty hot on the inside. If we didn't have the barrel clean to start with then I would be pretty concerned about the groceries. Other than that situation, I think you are quite right in feeling its a non issue. I run a couple skids of lump through my smokers each year and it doesn't happen often but it can.
Bottom line- build it to specs you can live with 'cause it IS your barrel.