I think the answer is TRUE.
RISC systems use fixed length instruction to simplify pipeline.
eg: MIPS, PowerPC: Instructions are $4$ bytes long.
CISC systems use Variable-length instructions.
eg: Intel $80X86$: Instructions vary from $1$ to $17$ bytes long.
Now the challenge is: How to fit multiple sets of instruction types into same (limited) number of bits (Fixed size instruction)?
Here comes Expanding opcode into the picture.
RISC systems commonly uses Expanding opcode technique to have fixed size instructions.