TUBI SPECIALI IN ACCIAIO MADE IN ITALY---is what the OP's "Viner" decal says

TUBI RINFORZATI GARANTITI ACCIAIO SPECIALE COLUMBUS---is what the "early version" decals say, known to be used on both SL and SP tubing

COLUMBUS TUBI SPECIALI RINFORZATI ACCIAIO CrMo CYCLEX SL DOPPIO SPESSORE--is what the later version (post 1979) SL decals say

"The nomenclature on the decal is exactly what Columbus writes on theirs, just without the Dove trademark."

Angel has the most complete collection of images of "oddball" Columbus decals I have ever seen, including many of "custom sets" drawn for a specific bicycle frame or company and nothing that looks like the "Viner" decal or that has that exact wording: Special Steel Tubing in simple English

ITALIAN CYCLING JOURNAL: Columbus Steel, Tubing for Frame Building