There's nothing you need to do to enable System V IPC, but on boot up "ipcs" always says:
IPC status from <running system> as of <date> Message Queue facility not in system. Shared Memory facility not in system. Semaphore facility not in system.
This just means that no one has yet used the Message Queue/Shared Memory or Semaphore facility yet. They'll be loaded on first use.
If you really want to have them loaded at boot time, add the following to /etc/system:
forceload: sys/msgsys forceload: sys/semsys forceload: sys/shmsys
In Solaris 7, ipcs will report the unloaded facilities as inactive rather than "not present in system".