That's probably not early enough. It takes a while before the CAA will have added your NR to the licence, and only once that's done can you initiate the 61.75 process. Which in itself might take a week or two.
I don't think you're correct there.
My part 61.75 licence doesn't mention anything about Day/VFR even though that would have been the restriction on my licence at the time that I got it. It simply says that all restrictions and limitations of my Irish licence apply. As I see it, once a restriction on the underlying licence is removed, then it's not caught by that phrase.
Also the poster give their location as Ireland. While they might have a CAA licence if they did their PPL in the USA, they probably have an Irish IAA licence. The IAA are actually quite helpful despite the fact that we all like to complain about them
If he rings them up and explains, they most likely will add the rating while he waits if he calls into their public office. They certainly did that for me in the past on more than one occasion.
dp