Looks great. I suspect your thermometer on your smoker is way off and you smoked at more like 325-350 to get that done in such record time. None the less, looks really good. Just keep that thought in mind when you smoke something less forgiving and much more expensive in the future. I like the Maverick dual probe thermometer units to keep an eye on everything. I don't ever really clean my
grill grates, I jack the temperature when I start her up to smoke the grates and then brush with a wire brush each time I get ready to smoke. Once in a while I will rub them down with crumpled up aluminum foil. I find that clean grates stick to some things way more than well seasoned grates. Now I see a lot of folks on here that keep their smokers spotless but not this guy. I think you are fine as long as you heat things up good enough to kill any bacteria that might be hanging around. Now I Q two or more times a week so my stuff never sits long so if you don't use your stuff much that might be a different story.