I guess I'm saying that trying to find fictional character motives based on something not visible in the film is more likely to be chocked up to prop maker error than anything else. We've got two very different Staff of Ra pieces (let alone the variations in the fertility "stunt" idol and that mechanical one with the human-like eyes) being passed off in the same movie as the same artifact and the easiest motive is saving money and making it easier to film. The Staff of Ra was a bad idea, IMO as they look VERY different (just changing the text would have been bad enough). And still people didn't notice. So, given you can't read the label watching the movie (unless the 4K version if/when it comes out changes that), I'd chock it up to the prop people rather than Henry Jones Sr.
But I believe Henry Jones Sr. was well aware his child liked the name Indiana and refused to use it since it's a bit of an insult to not want his father's name. I don't think he just discovered it in the movie. Whether he'd put it in print or not is hard to say if he thought it actually important. He did call him Indiana when it was really important (to save his life) and I think he placed great value on that diary getting there quickly. In other words, I wouldn't worry about it too much either way.
