I would be careful around lead weights. Some might dismiss it as no big deal, but personally I don't use lead weights and I use lead free solder. If you are to use lead weights, I would wrap tape around it so that you don't come into direct contact with it normally. Lead is a strong neurotoxin that stays within the body. It enters the body through ingestion, so be sure to always wash your hands after handling lead. Low levels of exposure might have no discernible impact on your health but that doesn't mean it doesn't have an adverse effect. Under normal circumstances, however, it's unlikely to get lead poisoning from simply handling lead weights in R/C cars.
"Lead is a powerful neurotoxin that hurts almost all body organs, particularly the kidneys, red blood cells, and central nervous system. In young children, lead retards the development of the central nervous system and brain.
Even tiny amounts can cause reduced IQ, reading and learning disabilities, attention deficit disorder and behavioral problems. "