Am I correct?
yes.
The size suffixes are consistent throughout NASM, for d* and res*. They match x86 instruction mnemonic suffixes for byte to qword. (e.g. psubd works with packed dword elements).
There's even an instruction mnemonic that uses o (oct-word): cqo.
y and z size suffixes obviously match ymm and zmm register sizes, even though the instruction mnemonics are now things like VBROADCASTI32X8 because of AVX512 masking granularity.
