supposedly...but there have been stories down through the years of "531" frames (that had the decals on them) which developed splits in the tubes along a...seam. Seems that some French bikes (of noted brand name) were the flagrant examples of this, but I'd bet there were others, from other countries, too. I'd also bet they were cropping up in the "bike boom" when a lot of corners were cut, especially by the big brands with tall orders to fill.