As another comment already states: for the most part, no. However, the GBA CPU (an ARM7) in a DS is used as the IO-processor for DS games, while an ARM9 is the

As another comment already states: for the most part, no. However, the GBA CPU (an ARM7) in a DS is used as the IO-processor for DS games, while an ARM9 is the main chip. On the 3DS the ARM9 is the co-processor, while a new ARM11 is the main application processor. Since the 3DS can also run DS games it still has an ARM7 as well and can natively run GBA games, even if that functionality was barely used by Nintendo.