It's not that simple, and coating isn't the only issue or necessarily the main issue. There are some uncoated lenses that have very good contrast and will hold up to enlargement.

My own sense, though, is that the classic lenses look better in most cases on contact prints, so I use them mostly for 5x7" and larger, which I contact print, and more modern lenses for 4x5" and smaller.

There are a few exceptions though. I have a 168mm ser. iii Dagor that's fine on 4x5" when I need its extra image circle. It's not as sharp as a modern plasmat, but when I need an approximately normal lens on 4x5" and lots of front rise, it's the right tool for the job. I have an 11.5" Verito that I use mainly on 4x5". I prefer the 14" Verito on 8x10", but it's not always possible to bring the 8x10" camera.