In general, it's worse than that. If you're in Y you need to pay to select a seat. Period. Even @ check-in. No, not kidding.

I believe they waive it for Oneworld sapphire and emerald, but not for ruby.

Business class can select for free, so they beat CW, CW there.

Award tickets are actually allowed to select for free in advance.

Oh, and the website blows... so even if you are in a category that gets them gratis, don't expect it to work the first time (or fifth). IME I've phoned OneWorld partners to get it done. Good luck.