It sounds like Walther would need to organise a base metal comparison, Harvey, and I'm not overly keen on sending it back to Germany to be honest. But I suppose that getting into the DNA of the frame is the surest way of knowing whether it came from the factory. Mind you, where else might it have come from? The Soviet State Western Copies Unit?!

If any forensic examination is to take place, the last place I would initially send it for such an examination, is Walther.
It needs to be done by a totally independent laboratory, and unless an earlier example is offered, and I accept my butchered LP53 may not be ideal test material, it is on loan offer, if needed, for any metallurgical tests, as I believe nowadays such tests can be carried out without destruction of the test sample, although I would have thought a small sample of frame material removed from the grip area wouldn't cause any damage to the working of the pistol, if found to be necessary.