Well, you couldn't see much into the exhibit due to bright sunlight, but I don't think so. On their website I believe they have a photo of their 1 speciman. Why the image on the sign is portrayed that way is a mystery.
we used to have a melanistic Geoffroys many years ago. We now have a lone female; at approximately 23 years of age, she is usually inside, sleeping in her bed. We (the keepers) are all very attached to her, and let her do as she pleases, even though it means she is rarely seen by the public. As for the exhibit, we are constantly trying to keep it pruned, but as you can tell--sometimes the plants win...