I don't know the answer to your question, but here's a thought:
Assuming that an replacement/aftermarket decal would not have the adhesive/staying power of the factory ones, would it not be easier to tape off and spray them with some $1.99 black spray paint?
I did basically the opposite, spraying the rest of the cap black and leaving the bowtie gold. You could also do it in Plasti-dip that way if you don't like it you can just peel it off. That would set you back more like $5.99 though