I just called Nikon (Japan) customer support today, and the representative said that the production of the 63mm lens had ended last month and there's no stock there, but that wouldn't necessarily appear on its website, which I personally don't know why because there are notices on other finished/discontinued products. He said 50mm, 75mm, and other current types in the current lineup are and will still be available.

I might have to look for a used one as a backup since I'm starting to like this lens a lot.