Anita,
I would have to see examples of what you are referring to as matte black, but I have had many examples where what appeared to be flat black enamel, was in reality very tarnished silver applique, sometimes appearing to be enamel, or painted black decorations.
Some experimentation through the years with pieces I did not really care about allowed me to polish the "flat black" to reveal an underlying silver design or trim. Much of this older glass has sat untouched for many decades, and as a result, what we see as "matte black" is actually tarnish. It obviously depends on the piece, but I have uncovered a number of pieces actually having silver trim and applied decorations, that appeared at first to be in the manner of "Tango".
As I sat and thought about it, I could not think of any piece of Tango like glass I have seen that combined a gloss finish base color with a black satin (or matte) finish glass or enamel. Both have always been a high gloss finish if the black was actually enamel or glass.
You see the same thing commonly on old Tiffin and Cambridge glass with the silver overlay on clear.... After a while it is matte black design over clear glass.....
Craig