No, although both are located in Washington, D.C.
The former name of RFK Stadium was D.C. Stadium
Actually, only RFK is located in Washington, DC. FedEx Field is located outside of DC in Landover, Maryland.
RFK used to be the Redskins' stadium before FedEx Field was built and took over the job in 1997.
RFK is now the home of DC United, Washington's soccer team.