It rather depends how specific the flavor of the ingredient is, though. Not everything has generic versions. "Maker's Mark" instead of "bourbon" probably doesn't add anything to a recipe -- exploring other bourbons is likely to give good results, although it may be valuable if the bourbon specified has particularly unusual characteristics that the drink is balanced around. And even Cointreau instead of triple sec is silly (in my opinion), although Grand Marnier is different enough to call out (and to expect some work needed when subbing). But for something like Green Chartreuse... it's a brand name, sure, but it's also what it is; there's nothing else like it, nothing else that you can use to build the same drink. And Kina Lillet is in that category. There are plenty of "brand name" drinks that were never popular enough to generate near-exact clones, and are gone to the giant Long Island Ice Tea in the sky.