After removing the plugin from the conductor, the packages are left in SSR routers.
After uninstall GRE plugin from conductor and removing GRE configuration from routers, the GRE package on the SSR routers still remains as is.
# rpm -qa | grep -i gre t128-setup-gre-1.1.1-1.x86_64
After removing the GRE plugin from the conductor, the packages are still seen in SSR routers. This is an expected behaviour for GRE plugin.