Nearly... for machines that have a fixed-size instruction, the whole instruction, both opcode and operand specifiers, could be fetched and loaded into the Instruction Register. It would not particularly matter what part of the instruction was where as long as the patterns were where the instruction decoding circuits expected them.

But the VAX does not have fixed-size instructions. The op-code, in fact, determines how many (up to 6!) operand specifiers are to follow. This hint should help you answer the question.