That would be a huge fail on Apple's part if they chose a company that cannot supply a product in line with demand.
I ordered a 42mm SS with black sport band for me yesterday morning along with a 38mm SS with dark blue modern buckle for my wife on the same order. After she thought about it some more and afraid that the date might slip even farther back, we cancelled the one for her that I ordered and she ordered a 38mm SS with white sport band instead.
Reason we were afraid that her ship date might slip even more past June is because there's obviously a supply issue with the modern buckle bands since none of the watches are showing anything sooner than June and buying the bands by themselves isn't even available right now.
We're hoping that somewhat soon we will see the blue modern buckle band available, and when that does happen we'll just get her a band for her watch. In the meantime, she'll just wear the watch with the white sport band (which will show up sometime next month instead of June at the earliest like she was looking at with the original order).