I couldnt find jsut the gasket on redcat's site.
but that doesnt mean that www.rufaster.com
wouldnt have it. if you cant find it on their sites, you could try emailing them.
another idea is going to a auto parts store, as you can usually find gasket material. then you just cut it to the shape you need.
the truck will run without the gasket, but will be loud/sound like crap and lose some of its power.