I can not comment on how it would work on your smoker. I have used Rutland black sealant rated at 800* with no problem, but I design my smokers around protecting the seal. ....so, when you are stoking up your fire with the lid open, do the flames contact any of the area that you want to install this sealant? If so, I would not recommend it.
Also, do you have a problem with paint burning off in the areas you want to install the sealant? If so, don't use it.
If no to either of those questions, then your probably alright to use it.