I think you're right about mustard. Lime also had brass hardware.There were nine original duffle kits: Carnelian, sunflower, emerald, cobalt, fuchsia, black, warm grey, parchment and camel. Coach may have issued more kits with the Spring line of duffles.
I think there are two that have gold hardware- camel and sunflower.
Duffles that have gold hardware are cognac, camel, sunflower, robin's egg, deep port, black violet and (I think) mustard.