If there is no documentation then how can we help?
Maybe you can't, perhaps someone have the same device or knows how to get this data.
I think we might be at the stage where anybody who asks you for the documentation isn't going to be of any help to you.
I'm not completely au fait with these devices, and I don't understand what you are trying to do, so I have a question. Why do you want a MAC address?
I do have a JY-MCU that looks exactly like yours, and it works, but I am not using it the way you want to.
As I understand it bluetooth devices recognise each other, get paired by the user, and talk. That is their job, and that is the way I use mine. No MAC address.
It appears that the JY-MCU label simply refers to the board with a four or six-pin connector, and the HC-05 module is fixed thereto. The HC-05 is what you might want to know about, but probably don't. As far as I know, there is no documentation for the JY-MCU, and there is no need for it. All you need to know is written on the back of the board.
Documentation for the HC-05 is herehttp://notes-application.abcelectronique.com/314/314-67142.pdf
and I can't find anything about mac address in either of them. I'm not surprised about this - yet