cargo rack installation

[Konstantine Bogach]

I found a rack from 5K Avant on a junk yard and first thought was "what
a luck". I started to dismount it and then ... oops... I discovered that
that car has fitting for the rack with interanl thread welded to body.
Not to mention ports in the roof for attaching the rack.  I did not pick
it up.
How difficult to install it on the car which did not have the rack from
factory?
If it is  very difficult  I will not go for it  but I can pick it up for
someone who wants it anyway.  I expect price to be $30 - $50.

Konstantin Bogach.