Wes,

Only have limited info in front of me now.However,here is what I have on the John M Davis of Johnson's Texas Spy Co.,later CoE.Morgan's Battalion.

Age 40 in March 1862 when enlisted in the Spy Co. Born Kentucky.

Discharged form the Spy Co.July 24,1862 by Terms of the Conscription Act.(All overage men were discharged,but of course they got most of them back later when the ages were extended)

On 1860 Census Collin Co.Farmersville.Wife Sarah? No slaves.
On Collin Co.,Tx Tax List 1867.Voter list Collin Co.Sept.16,1871 age 51 Born Ky.

Pvt.Co.E 3rd Texas Mounted Vols.Mexican War.7/2/46-9/9/46
Enlisted Cedar Springs(Possibly Dallas Co.)

Is this your John Davis?

MWT