1999 is exactly right in the period I had imagined for these which was sometime between 1995 to 2005. Impressive that you have been able to see the date on them. Is it because you used the zoom of your camera on the stickers of one that's off? The ones I saw in 2019 were almost all spinning except the CP56 with the short pole and it's located too far away from the glass for me to be able to read the stickers even with a camera zoom plus the stickers on some of them are very dusty.
My camera does not zoom very much
I was able to see with my own eyes because there was good lighting I can even see it on the short pole one and the second one also off but on a longer pole