last year I overhauled a friends bike and she had been told that she needed a new hub. The cones were pitted, but after a lot of searching through bike store cardboard boxes of orphan cones, I found two that were very similar in shape etc to the originals, which I had in hand to compare.
no guarentee, but this is probably your best bet, physically comparing the old cone to what is around in drawers or boxes at bike stores.
Even if its not an absolute match, if reasonably close, it should be fine.
good luck with that , or the online search thing.