Mr. Carlock's book is not a very informative, detailed or accurate source. Having studied this regiment for several years, I was sorely disappointed in Mr. Carlock's publication.
Mr. Sumrall's book is a very good source. It has the first flag of the regiment depicted. 'Texas Flags' by Dr. Robert Maberry, Jr. shows an actual photograph of this same flag, plus a depiction of the McCown pattern that the regiment carried into the battles of Richmond and Perryville, Kentucky, and Murfreesboro, Tennessee(Stones River).
There is still some speculation as to whether they carried the Polk pattern flag or not. When Ector's brigade was formed, the 10th was carrying the McCown, and the 9th Texas Infantry was carrying the Polk. AS the Polks were quite often made in the field, there's a good chance they did carry it, too.
The last flag they carried was a Richmond Depot ANV variant, made in 1864. It was one of four that Col. Young of the 9th Texas Infantry presented to the Texas regiments in Ector's Brigade after he returned in April of 1864 from Richmond. All four varied an inch or two in length and width, but the placement of the stars and the method of construction were the same. There's a picture and detailed diagram of this flag on the 9th Texas infantry website. The 10th's and the 14th Texas Cavalry's flags are in the Museum of the Confederacy, listed as "unknown Texas Cavalry flags".

Preston Furlow