>>28609741
1) RC F GT3 was already developed and homologated by the time the LC came out.
2) LC wasn't built for FIA GT3 or any sort of racing.
3) Toyota would basically be telling their teams that they wasted time and money to unfuck the RC so soon after the car launched and work on fixing the new car.
4) LC would need its own homologation.
5) Evo updates for old cars is cheaper and easier to get FIA approval.