I have some two-colored perfume nips with names on them, so perhaps the following will help. I am pretty new to Basenotes...
yellow/baby blue: Esperanto
black/red: Midnight
orange/baby blue: Nosegay by Dorothy Gray
black/gold: Black Satin by Angelique (1958)
red/white: Fourth Dimension by Helena Rubenstein (1956)
gold/medium green: White Lilac by Mary Chess
white/gray: Golden Chance by Harriet Hubbard Ayer (1949)
purple/black: Consent by Charbert (1952)
orange/baby blue: Dark Brilliance by Lentheric (1946)
the following I'm not sure about (most of the paint has flecked off or they look to have the same color on both ends of the nip:
black/white: Shocking by Schiaparelli (1937)
gold/gold: Folie de Minuit by Lanier (1955)
baby pink/baby pink; Silhouette
red/red (?magenta/magenta): Envoy by Lanier (1955)
gray green/gray green: Virtuoso by Lanier (1950)
By the way, if anyone in the continental US would like to try any of the above nips, I have one of each (2 of Silhouette) and would be glad to share. I found one of my new favorite fragrances through a vintage nip (Blue Carnation by Roger & Gallett-- a gorgeous carnation soliflore, deep clove scent) -- I now have a partial bottle of that from Ebay and, again, would love to share free decants. Contact me if interested. Peace, love, and vintage scents! Lisa