correct history, shutdown(8) appeared in 4.1BSD before 4.1c

correct history, shutdown(8) appeared in 4.1BSD before 4.1c

"shutdown
Is a new command which shuts the system down at a specified time."
Bug fixes and changes in 4.1bsd
May 10, 1981
from bitsavers bits/BSD/BSD4.1_bootable.tap.gz
/usr/man/man0/changes.4-81

There may have been some confusion when checking against CSRG archives.
The 4.1 there is 4.0 with a "4.0.upgrade" directory with 4.1 files such
as 4.0.upgrade/etc/shutdown.  And 4.1a isn't a full tree.
In SCCS shutdown.c starts on Feb 7 1981.