The artifacts are from the museum's permanent collection so you may have seen some of them before. What's different is that they're trading on the popularity of Black Panther. All of the signage is in a comic book font and you'll see a few word balloons and such.
They have a copy of the Black Panther comic in the display as well as some comics published in Africa. It's not a major part of the exhibit though.
Their brochure for the exhibit, although it's folded like one of those easily-ripped pocket-sized maps, also reflects the comic book design motif.
You might not want to make a special trip to see it but if you're going to the Freer's Hokusai exhibit, you definitely should pop in.
The museum's description of the exhibit is on https://africa.si.edu/exhibitions/current-exhibitions/heroes-principles-of-african-greatness/
My pictures from my Thanksgiving visit are on