Hi Patti,
Bourland's regiment should have carried some sort of Confederate flag - but what that pattern was is purely conjectural.
As for the state militia units, not too sure. I actually doubt it would have been state flags as there were simply not that many used that we have found - and the Dallas newspapers in 1861 had to run articles describing them since so many newcomers had come to Texas since 1839 when it was designed they did not know what it looked like!
The rank of ensign is a bit enigmatic. Prior to 1864 it was the same as Third Lieutenant and without any flag responsibility. In 1864, the Confederate War Department created the rank for the unit color bearer but without command responsibility. It was rescinded in 1865. So be careful with the "ensign" ranking as it can mean two different things.
Greg Biggs