Just adding a thought or two to the stripes and plaid discussion (although kind of jokingly brought up, the subject is really a good addition to the authenticity question.)
Most pictures I have seen of "cowboy" clothing show that they wore a mix of patterns regularly. Was this dandy-ing or just practical, to wear out an article of clothing before replacing it?
You had to buy what ever style was available, or make an article of clothing with what ever material was handy. You wore a mix of colors and patterns because it was all you had. You were lucky if you owned one set of clothes for everyday and one set for special occassions. Buying ready-made clothing was still extravagant, though becoming more readily available where trains regularly passed through. Since the military was the major user of "ready-made" clothing, those people living near military installations would have access to excess inventory. In many cases, locally made clothing was less expensive than buying "ready-made".
I'm sure that just like wishing to own a set of pearl handle pistols, many cow-pokes felt a need to dress up with a new set of clothes when they reached the end of the trail, to signify that they had money in their pocket and were able to pay for drinks and "entertainment" from the women-folk.
Town folk, on the other hand, were more subject to the Victorian tastes (being more "civilized") of wearing suits with waistcoats and ties most everyday, and would have more tendencies to wear matching patterns and colors. Some of those worn for everyday were in patterns that would be considered garish by modern standards. Large "window pane" patterns were commonly used for "sack" suits, so it seems that even the prim victorians found ways to stand-out while still being "proper".
I'm finding that I like a mix of clothing styles and patterns, but admit I dress more like a townie most of the time. In summer though, I tend to dress more "cowboy".