I guess you got to really be a big fan of Fire Fly to understand the brown coat shirt thing. But the special effects were good. I watch Fire Fly some but don't remember anything about a brown coat thing.
I looked it up.
"Browncoat is a term with two meanings. One is a nickname for the Independence fighters in the television series Firefly.[1][2] The other refers to fans of the series."-http://en.wikipedia.org/wiki/Browncoat
"In the series, Browncoats were named after the simple brown dusters the soldiers of the Independence faction in the show had worn as uniforms. Conversely, the Alliance's soldiers were called "Purplebellies," because of the purple-tinted body armor they wore on their chests."-http://en.wikipedia.org/wiki/Browncoat