Is your M.N a 7016/0?
Does it have a flat case back, like on mine?
Have a look at Dr Strong's review on the Tudor M.N, my friend ( Go to New Blog Post on the right part of your screen and see the link to Tudor M.N ).
I did some searches, and had the confirmation that the 7016/0 M.N was released in '74 only, and that this watch came with the black dial, only.
Some received the blue dial, though, because the black dial was ruined, but it originally came with the black dial.
The later M.N ref 94100 always came with the Blue dial.
So, what is the reference of your Tudor M.N ( the ref is engraved between the lugs ).
Best,
Nicolas