is this copper maran a rooster

Yep, cockerel.

 

Yes, that is a rooster, the easiest way I've found to tell is the saddle (feathers on the base of the tail) and hackle feathers (neck feathers). In roosters they will be pointed and hens they will be rounded.

Here is a photo that shows the difference between adult chickens feathering (not my photo, I found it on a google search)

 

Handsome cockerel.

 

Definitely a cockerel.

 

Cockerel

 

His huge red comb and wattles and all the copper already showing on his neck. My black copper Marans pullet is about the same age, maybe a little older, and has a very small, barely pink comb and no wattles and is just starting to show a smidge of copper on her neck.