Seeing that the 7th SC arrived in Virginia in summer of 1861, it was probably the 1st Texas Battalion (later Regiment), consisting of the first eight companies of Texans to arrive in Richmond. More companies arrived later and the battalion was organized into a regiment.
Truth is, they weren't all
that rough. The three Texas regiments that comprised Hood's Texas Brigade mostly consisted of young men who had been born out of state (as most people living in Texas were at the time), coming from middle or upper class families. The 1st Texas was mainly recruited from East Texas, which is geographically similar to Northern Louisiana. Though some would fit the character, not all were your stereotypical western frontiersmen. They were, however, some of the youngest and most determined troops to come out of Texas - volunteering with the intention of fighting in the East, where they expected the decisive battles to be fought.
When these guys first arrived they were wearing all sorts of civilian clothes mixed with company uniforms, as was typically the case. Also many brandishing huge Bowie knives and wearing wide-brimmed hats pinned up with stars. So they probably put on quite a fearsome appearance.
New uniforms were soon issued in place of those, however. For example, here is a photo of men from the 1st Texas in winter quarters at Dumfries, Va., winter of 1861-62. They wear your standard frock coats and forage caps, but still with a bit of Texas mixed in - neckerchiefs and Texas stars in the caps.