Quadra fire 1000 snap disc replacement

Hello All!! I am back to report my house has maintained a balmy 74 degrees in the single digit temperatures here in Michigan!! Sooooo, now I am going to start tweaking things. I bought all 3 snap disc's and would like to replace those. Is there anything special I should know about replacing them? And upon cleaning and inspection, I found that my fire pot has been upgraded from the original ceramic one (lucky fricking thing there!) but it doesn't have a gasket where it sits. It does call for one, what would or could that cause if I don't put one on? Thanks fellow Pelletheads