Hi Vern,
I also enjoy a good discussion and disagreement is healthy. I don't know of anybody that argues as friendly as we do
!
You will see a lot of variation in the alteration of the safety marking. Heinz Ahlers has made a pretty good study of them. The depth and width of the machining will vary, some are re-blued and some are not, and some, as in the case of mine, the area was welded back up and re-machined after removing the marking. The alteration obviously was not done as a lot and not performed at the same facility or with the same level of care.