The other Owen David Griffin (recorded as OD) is in
footnote.com:
Civil War Soldiers - Confederate - TX
… Eleventh Cavalry (Young's Regiment, Third Cavalry) » G » Griffin, O D » Page 2
Given Name: O D
Surname: Griffin
In remarks it says Owen D. Griffin deserted in Oct. 1861
My Owen David Griffin was gone at least until about June 1865...as next child is born March 1866.
On the 27th Cavalry web site it shows the following on the roster page:
http://gen.1starnet.com/civilwar/27cvrost.htm
"Note: Many men appear to be in 2 different companies. It appears in some cases that companies M, and N are duplicates of other companies. It is not known at this time why the duplication and creation of other companies like this took place. "
Griffin, Benjamin, Capt, Co. F
Griffin, David, 2nd Lt, Co. I
Griffin, David, 2nd Lt, Co. N
Anyway, thank you both Patricia and Bill for your help...this is all thoroughly confusing to me as I have not done that much research on the Civil War.