I've never had anything with a label saying that, but I was wondering if this was some kind of licensing thing? This brought to my mind a 1960s Spengler mail-order catalog I have. Spengler at the time was a higher-end mail-order business here - my mom remembers it as having been mostly out of her reach financially. It features a lot of dresses and coats by Jacques Esterel and Emilio Schuberth. In the introduction, they describe this as having a special partnership with these couturiers and that they would send their buyers twice year to their ateliers, to choose 30 to 40 creations by each and that they would then be "interpreted" by Spengler's own producers. This is an instance where I would think a "styled by" label would make sense...
Karin