Oh dear!
The new oOple forum seems to have lost the ability to edit a post. It just replaced the text instead.
So I'll start again. The TC02C does not have a separate gear cover, it is an integral part of the body shell. Also, there are no fixing points on the motor plate to mount a gear cover either.
If you have the correct body shell then it will keep enough of the sand out to keep your gears healthy.
The two shells, now in the previous post, show "Penguins" two versions of shell for the pre-Evo verions of this buggy. The yellow one fits the narrow, TC02C, and the other one fits the wider, Lupuz/Mad Monkey. They are both in the order of £12.
The yellow shell now has cutouts in it, to accommodate a gear cover, which I needed to fit after switching to an Avid slipper. Prior to that no cover was used as the spur gear was well clear of the shell.
It now looks like this: