If you can get it sandblasted inside and out out to " white" metal, I would highly recommend doing so. It's really not that hard to find someone to do this, and probably won't cost but about $100 bucks or so.
It will help keep you from having all the paint issues so many people complain about, especially on the firebox, and will give you a cleaner, more sanitary look to the inside.
I usually blast the smoker, the paint the outside and just the inside back side of the door, including all of the flanges. Then install my door seals or gaskets, and once they are cured, I will spray down the inside with some cheap vegetable oil and let it soak in for a little bit.
Then I'll start with a small fire, and keep it below 200 for a couple hours to let the paint cure real good before cranking it up to around 400' , then start stacking layers of vegetable oil ( with one of those quart sprayers from Home Depot ). And keep doing that for a couple of hours until the metal gets a nice dark color .
This includes the grates, top and bottom of them as we'll.
Then rinse it out with a water hose while it's still hot to get any crap out of it that may be still in there, and one all the water is baked off, stack a couple more layers of oil and run it around 300 for as long as you feel like it, just make sure all water is burned off.
Then cook, and never worry about seasoning it again. ( except your grates if they are not stainless)