ok got any idea how these mount. shoulder belt hanger

i have these. it would appear that they might get placed under the headliner moulding trim but that does not work. my 72 had original cardboard liner, just changed to regular vinyl liner with bows. still have original molding for top. seem no place these can fit. i thought about drilling a screw in the bottom and bolding to the out croping on the roof under the liner. but is there something im missing?upload_2021-8-23_13-28-24.png