The warning doesn't matter to me, even the very earliest of the Sixes had the Ruger brand name on the barrel in the same spot. It's just that Ruger made it a paragraph in 1978, instead of a sentence
It adds a point of "seperation" for collectors, you will often see the term "pre warning" on this forum.
In recent years, Ruger has reduced the warning on the new GP100 to maybe 3 lines and it's more "clean", if that's possible. It's no longer a 6 line block of writing.