Vintage YSL Burgundy Emblem Duvet Cover With Zipper

Length 82 1/2” Width 80” This is from my Mom. I know she’s had this for quite sometime. I can’t vouch for the authenticity because I don’t have a tag. I do know that this pattern was quite prevalent starting in 1979. Her home is pet and smoke free and she’s pretty meticulous. There are pictures of a blue mark. Can’t seem to find another that would effect the piece.