Thanks for the reply, Abrac.
Interesting to hear that other people have the different addresses thing too. I have to say, I was pleasantly surprised at the lack of lamination and the calligraphy titles when I opened up the box to count the cards. Before this I have only ever owned a super slick plastic laminated recent printing with the non-handwritten titles, and those two changes make a BIG difference in how much I like the deck.
I don't have my other RWS with me at the moment so I can't compare the greys, but it does sound similar to yours. Makes sense what you said, the deck having been put in this box at the factory because of leftover stock or whatever.
I guess the unlaminated cards would still put it at roughly 1980-1985 though, right?
edited to add: I don't know if all printings have this, but for what it's worth, the second extra card has a tartan back and a completely blank face.