I'm guessing the OP's reference to "brass-plated" lead bullets was a typo.
The most common commercially available article is "copper-plated".
Copper-plated lead bullets are prohibited in CAS-competitions because they cannot be readily distinguished from copper-jacketed bullets.
What is allowed in CAS is "powder-coated" lead bullets.
They usually come in all other colors except "brass", "copper" or "golden", and can be readily identified.
The powder-coating does the same job as the copper-plating, especially at CAS-velocities.
Finally I'll add that neither copper-plated nor powder-coated bullets look "cowboy", in my opinion.