I may be oblivious to plot points that are staring me in the face, but this is the sort of trivia I notice: the difference between the US version of the Serenity logo (left), and the UK version (right).
I like the US one better, but …
The logo shows up in the movie, by the way, as the painted insignia on the side of the ship. Which was odd, because (a) I think it’s the only Roman lettering we see (everything else was either Chinese or something Futuristic), and (b) it was a bold and vivid stroke of color on the otherwise worn and beat-up ship. Now one could argue that Mal would want that logo to be as bold and vivid as possible, but it still looked a scosh out of place, as if it should have been more weathered.
I think it was the US version — but I might have to go back and watch the movie several more times, just to be sure.
I note that the Browncoats site looks to use the “UK” version.