Its doubtful that that item was/is a casting
Speaking as a "boffin", I think it's doubtful too. FAR 25.621 specifies factors to be applied to cast parts, and they are pretty penalizing from the perspective of weight and inspection. Though I have approved designs incorporating cast parts, these parts were in very low stress applications, with low failure severity, and easily inspected. I have changed the production technique for several parts from "cast" to "forged" to improve the product and save weight. And yes, we specify some holes and surfaces pretty closely too. I have nothing to do with Boeings, though it is very unlikely that I would approve a cast part in that application.
Of course, once a part is approved as a part of the type design, as said, it is not the role of subsequent technicians to necessarily understand how the part is made, and to make their own determinations as to airworthiness, other than in accordance with approved techniques and standards. Just put the right part in the plane applying the correct technique.
We all have a role to play in the safe operation of aircraft. For some of us, it may be at the beginning, specifying the manufacturing techniques and standards of quality. For others, it's maintenance or operation of the aircraft. We all have our own "areas" in which detail is important, and misunderstanding must be prevented.