Quoted:
It really depends. I have seen gold, brown, copper etc. Magpul coyote brown mags go well with most of the DDC. You might want to wait to see what color your rifle is.

Quoted:
DDC has a variance in shade due to the anodizing so there wont be any specific color match like you would have if it were cerakoated.  I'll include a link below to our guide on what to expect with DDC to help.

Geissele DDC (Desert Dirt Color) Disclaimer

-GACS

Quoted:
Like GACS said, DDC is anodized, not cerakoted. It's the same process normal black receivers use to make them black.

Basically the aluminum part is submerged in a bath of some acidic liquid, and then an electric current is applied. And particles from the liquid bond to the surface of the part in a way that not only gives it a color that stays on and resists wearing off, but unlike cerakote it also improves surface hardness and corrosion resistance.

Problem being that anodizing in any color other than black is extremely difficult to control the exact coloration between repeated batches. That's why most companies like to cerakote things, since it allows them to guarantee exact repeatable and matching colors so their goofball customers don't shit their pants and get pissed that their stuff doesn't match because one thing is a slightly darker shade of whatever than something else.

Geissele doesn't care about that, and they cater to customers who don't care about it either. And rightfully so, because it's kinda dumb.

As long as you can learn to be ok with slightly mismatching colors and not shit your pants that your upper and lower are slightly different shades of brown, anodizing is the objectively superior way to add color any aluminum part.

If you'd like your mags to match the exact shade of brown on your rifle, you'll need to wait until it arrives to see it. Personally, I think mismatched part colors look cooler anyway.