Could also maybe be a pair of barrier reef clowns?!?! Can try Google to confirm
Their faces will get all black as they mature.
Perhaps "age" would've been a better choice instead of "mature". Lol.
I am pretty sure right now they are a misbar version of this:
http://www.bluezooaquatics.com/productDetail.asp?did=1&pid=6576&cid=361
However, as they get a little older they will turn into this:
http://www.bluezooaquatics.com/productDetail.asp?did=1&pid=730&cid=361
I get what you are saying about size and mating but those aren't pre-requisites for black faces or vice versa.
I think the orange face has a lot to do with diet. I have bought pure black clowns, brought them home, and after a week or so they will get an orange face. It's happened with every one I have bought. Not sure which food it is since I feed such a variety.
How long have you had them? Are they hosting?