The 1.0 rtr had one hole for the rear brace to clear the roto start on the back of the motors. The 1.0 RR has 2 rear chassis screws. For some resin when they made the new longer 2.0 rtr chassis they left it with 1 whole. Even with the motor having a back plate.
1.0 rtr buggy has silver chassis and silver towers one rear brace hole
1.0 rr buggy has gold chassis two rear brace holes
2.0 rtr buggy blue chassis and towers with one rear hole
2.0 RR buggy black chassis and towers with two rear holes.