The special new resort booking windows for Riviera were only for a limited time and have since ended.
If purchased direct, yes you can book any non-home resort beginning at 7 months out from your intended check in date.
If purchased resale after 1/18/2019, you can't book Riviera at all using those resale points. Resale purchases prior to 1/18/2019 do have access to Riviera.