It's always good to search other applications for a part GM used on it but never made public. Knowing what cross-references can help you find hard to find parts on other obscure vehicles that nobody cares to pick on at the junkyards. But that is the hard part, knowing which part cross-referenced.
The alternator caps are black and red. They used the same part numbers from the 70s into the 80s. Most of the early 80s used red, and then they went back to black at some point. Although I have learned that it's a crapshoot on which color you got.
You have to be careful with some of the cables as well. Many G-bodies used red-headed ends on the black positive cables, but the cables were smaller in diameter in comparison to some of the older fare. They could pass for a vacuum hose they're so small. I've seen where someone had some custom cables made, but they used contemporary "fat" cables instead of the thin ones and still made the positive cable red. Fatter is normally better when it comes to fuel lines and battery cables, but they still looked a bit off. Of course, if your cables are mangled, nice looking ones can compliment any engine bay. It just depends how "factory" you want your car to look.
Going all black for 1985 batteries isn't exactly accurate. Maybe it was for some Camaros, but for most G-bodies, the tops were black, but the case was still white. I kept my original 1985 HD battery with a black top/white case. But I was under the impression there were white case Freedoms used in 85 Camaros as well as I'd seen a picture of an original 85 Iroc battery. Problem with knowing which battery your car had is tough as most people replaced their batteries and traded in their old ones and don't recall which battery came original to their car.
A guy on many of the forums with user ID of Burd sells toppers. The black ones are simply the blue ones he had made but they're painted black. Very nice reproductions, though.
Burd finally came out with some 85-style battery toppers in black. I had been after him to make some for quite some time. He did so right after I took matters into my own hands and made my own. I took a Freedom II black topper he sold me, and pulled the decals off and I made my own.
My prototype below:
And an original 1985 Iroc battery. You can see, they had a white case. (courtesy of thirdgen.org)