Thanks very much for your help, To be truthful I am a member of the "if its not broken don't fix it" brigade and didn't take off the other caps to inspect them.
But the Cranshaft damper was in very poor condition, now renewed. recently I took the car to a rolling road, where timing problems were discovered, the wrong kind of plugs fitted, and the secondary jets never coming into play, because the geometry of the new holley carb accelerator was wrong all now sorted and the difference in the cars performance is manifold.
So it would seem that these faults or some of them could be the cause of the coppering on the bearing.
Just as an aside I have genuine Factory paperwork regarding the engine in my car, the original engine dropped a valve destroying the engine.
A "new" one was fitted by the factory, but when I looked at the bearing it wasn't a standard size but 10 though under, I doubt that the owner was informed!!!