After looking at some more tracks (like on the sampler, a few of which might be questioned), I’m inclined to say you probably don’t have too much to worry about really. There are so many variables it will probably matter less rather than more in the future. But I still think it’s worth looking at your upsampled files after mastering, and maybe ask the question to HD Tracks or other hi-res sellers what their policy actually is, and is it changing.