You don't have to be that careful with it, the older GT is still an awesome basher..just keep an extra spur gear on hand just in case. Yes, the black tub chassis is older than the flat blue one. You shouldn't have a problem finding a body on Ebay for it. I'll be home from work in a few hours if...
The blue chassis is a bit longer and much stronger. The black tub chassis has some flex which can destroy your spur gear and it doesn't handle quite as good as the blue.
Looks like a black tub chassis GT. I think TBG makes bodies for them on Ebay but I don't think the GT2 body or most others will fit without it looking a little strange.