When are shadow accesses *required* in the 280x CAN module?

As described in the manual, all registers must be handled with 32 bit accesses.

However, is this only relevant to bitfield accesses (e.g. ECanaRegs.CANMCR.CCR)? If so, are read-modify-write operations (such as ECanaRegs.CANME.all &= ~(1 << mbox_num)) OK?