Anyone fitted roof bars to Galaxy / Sharan 1998 type?

[Portuguy]

My oldie 1998 VW Sharan model doesnt have the roof bars( longitudinal ) factory fitted . Id like to fit a set and i see some rubber gromets in the recess roof gutter which hide the holes plus two metal flat blocks each side . Does this mean they require bolting in place from inside the vehicle and removing the interior roof trimming?
Thanks for reading this and any advice.