There is at least one man missing from this roll, http://files.usgwarchives.org/la/pointecoupee/military/artcob.txt , Benjamin F. McKittrick.

McKittrick, Benjamin F., Pvt. / Com. Sergt., Pointe Coupee Arty. La. En. July 13, 1861, Baton
Rouge, La. Present on all Rolls to Dec., 1861. Apptd. Driver Aug. 16, 1861. Federal Rolls of
Prisoners of War, Captured Island No. 10, April 8, 1862. Forwd. to Camp Douglas, Ill., Aug. 1,
1862. Transfd. to Vicksburg, Miss., Sept. 2, 1862. Exchanged from Steamer John H. Done, near
Vicksburg, Miss., Sept. 20, 1862.

Source:
http://lascv.org/bindex.htm

I've found no further records for B. McKittrick, you may wish to post a query on the Louisiana Board regarding the McKittricks in the Pointe Coupee Artillery.
http://history-sites.com/cgi-bin/bbs53x/lacwmb/webbbs_config.pl

The 1860 Census Records of East Baton Rouge Parish indicate Benjamin and Peter were probably brothers.

Edward McKitrick 47 - Born PA
Julian McKitrick 43 - Born PA
Benjamin F McKitrick 20 - Born OH
Edward P McKitrick 17 - Born OH
Joseph F McKitrick 13 - Born OH

Hope this helps,

Mitchell Sanders