Anyone found a good match to their NFA upper?

I've got a NFA Side Charging AR-9 LRBHO stripped billet upper, whose finish is described as "Matte black hard-coat anodized per Mil 8625 Type 3 Class 2", and a raw unanodized lower that will need painting.

To me, the upper actually looks kinda glossy, or at least semi-glossy...when compared to some other anodized black rifles.

I'm trying to find a Duracoat color to match.....and I'm torn between "semi-gloss black" (which they describe as their HK color), "gloss black", and "slightly darker black".