This is true. As I've mentioned before, I can see why a lot of people feel the BC is the more accurate one because there are some scenes (particularly when they were fighting outdoors in the rain) where the suit appeared black. However, a lot of this is simply due to lighting and isn't the actual finish of the suit. Once they got indoors, you could see that the suit was more grey in color. As posted earlier as well by someone, when on display at conventions, the finish and color of the suit matches exactly what the regular version figure is.
This sort of brings up in my opinion another question though on accuracy. What is considered "accurate" now? How the suit is intended to look but doesn't necessarily reflect that on screen due to the tones and lighting used? Or how it actually comes across looking on screen, regardless of what the intended color is supposed to be?
For instance, the MoS suit. The colors of the suit in the film many times appeared very dark and muted, but the "actual" color of the suit (which I feel the stock MoS Supes figure reflects) was this:
So when we say "film accurate", do we mean what the actual colors of the suit are, or how they come across on screen due to various lighting effects and tone?
Although with the armored Batman suit, there are also several times on film where you can clearly tell the color of it is dark grey, as it actually is. As was mentioned, the gloss finish also makes the scuffs look way more pronounced than what they actually are, at any point in the film. Even when the suit at times appeared black, the cuts and scuffs never looked as pronounced as what they do on the BC figure.