My guess, roo. I have a Black Copper Marans x Cuckoo Marans sexlinked roo same age with the same comb as yours. Also it looks like he has the tell tale white spot on his head. This usually confirms a roo. IMHO.
Can you post a full body shot? Males are more white then black and females more black then white. Also a shot o their legs. We have 3 cuckoo too who are supposed to be girls and I am worried about two of them
Here is a pic. of my almost 4 week old Black Copper Marans x CCL, not the same chick as mentioned above but they look almost identical. The rosy comb on yours is also a giveaway for a rooster I believe.