No. Unless cited otherwise, index references to the 1st Ala. Cav. seen here are always C.S.A.

As far as the 18th Alabama and Missionary Ridge, the 18th Alabama belonged to Clayton's Brigade, posted on the far left of the Confederate line. The 36th & 38th Alabama were left to guard Rossville Gap, while the 18th and 32nd/58th were some distance away on the ridge to the right. After a delay crossing the creek between Lookout Mountain and Missionary Ridge, Hooker's Corps advanced on this part of Bragg's line on the afternoon of Nov. 25, 1863. The two Alabama regiments could not hold the gap, leaving the rest of the brigade to be overwhelmed as the Union force turned north along the ridge.

Had Confederate lines not collapsed in the center, they would have been enveloped and captured by Osterhaus' Division moving north along the eastern face of the ridge.

I believe seeing a number of men from the 18th Alabama who surrendered while the regiment was on picket near Cassville GA about May 18, 1864. Many of these were conscripts, some being former members of the "City Guard", a provost company formerly stationed at Selma AL.