The sleeves do come pre-printed. The ones we ran today are just demo graph paper with horizontial and vertical lines to show that the shrink is square on the bottle. (if that aint an oxy moron what is?)
Heres a sample of a finished product we run with a printed sleeve..This sleeve is Black on a cheap white bottle. Perfect shelf presentation.
https://www.neogenix.net/supremacy-p-78.html?