just an historical note: there are multi-thousands of individual frames, from hundreds of builders, that used high quality DB tubing for the 3 main, and lesser grade stuff for the stays and forks. In early days it was Columbus with Falck stays and blades, later we got all those "Tre-Tubi" framesets.
Word is that a LOT of very costly high-end frames that had the "All-Columbus" sticker actually used Falck and the like for the stays and blades cause nobody would know and the big-name builders saved a few Lire in materials cost. Technically they didn't lie since the decals didn't specify how much of any frame was Columbus, it was just implied that the entire thing was.
People who owned and rode them never knew either, and loved their ride quality just the same. If they bothered to weigh the bare frame, they might have had suspicions, but Falck wasn't as heavy as some of the cheap Hi-Ten or common steel.
Early Reynolds 531 decals were more content-specific and maybe the builders who used 531 were more inclined to honestly divulge the exact content, but maybe not.