My seal is pretty charred too, but I have not had any issues with holding temps on long cooks. It might be me, but I haven't noticed any issues at all. There shouldn't be anything else that is messed up.
If anybody is ever in my area, I am more than happy to share the lump. It's nice knowing he is friends with the guys that make the lump. I'm usually in the same boat as everyone else with supplying the food and booze.