Back in the LP era, I produced a record and worked with the mastering and cutting engineers. The rolloff started at about 15kHz and tapered off smoothly. I made a point of asking about it because back then, I didn't know as much and I thought maybe the rolloff wasn't necessary. They explained that it was to prevent premature record wear (which equated with returns). The roll off was applied automatically when the disk was cut, it wasn't done as part of the mastering.
Today's audiophile pressings may be different. But I don't know why anyone would want an LP of a digital recording when they could get full master quality with no compromises on CD.