Sort of is, because it it’s official, it’s just a normal card, if it’s something else, it is more weird than normal. But, if no one knows, and it can’t be tracked to be official, or to show it isn’t, then there’s nothing more to do then. (I think many here don’t like the idea someone storing the addresses and sending anonymous stuff later, therefore it would be “nice” to know it was just on official without id.)
Of course if it’s just one in 10 years, maybe id missing, which I believe it was, perhaps the receiver already let it go and be forgotten, and it was just acute reaction thinking the worst scenario.