re: I don't think so...
Yes, you may be right. I'm trying to get the original data files, but the jp2 is 420 Mb and it is locking-up my machine when I try to open it.
Other explanations include dark dust or fresh black lava filling a crater in a pale dusty plain, but I'd expect to see SOME textural features. If I stretch the contrast to the absolute limit on the jpeg they have released, I get some detail, but it's at the noise limit so I'm loathe to trust it without going back to the original data stream and getting raw, uncompressed intensity values.