It's a sticker, never been a plate. In fact I think it'll look hideous if it was an inlay in addition to the zodiac sign/engraving plate.
As far as if you're supposed to peel it off, I don't think you're supposed to do it or not. It's the same as the seal on the metal box - are you supposed to peel it off, or leave it? Or may be similar to the 'intel inside' and 'windows' stickers that get put on computers - some people peel them off, some leave them on to wear off. BTW Thiers-Issard puts stickers on some of their horn and wood scales too.

Most vendors don't really bother to retake new photos when there are some changes to a razor model. I think they should, but I doubt that it'll happen any time soon.

As far as why the box was opened if they haven't done anything to the razor, you should contact the vendor. My guess is that they'll say they've opened it for inspection before shipping it, to ensure there aren't any defects.