Help decoding the fender tag on my LP27D7

Harold Tarter said
I am having trouble with a couple of items on the fender tag, I can't find any information on Z2 or the 4 of the tire size 284

View attachment 1716133698

I see Z in 66 and 68 is special paint treatment. I don't know why they would have left that info out of the 67 listings.