Space stations, the advantage is that they don't use shipyards, the drawback is that they can't be refitted?
Another advantage is that they don't have armor, which makes them lighter and cheaper. (And also, obviously, incredibly fragile in combat.)
You can use shipyards to build stations if you want to, subject to the same size and tooling rules as regular ships.
In fact, I like to build my 25k freight barges and 100k colonist pods in a shipyard--and I can actually build either one with the same yard.
You can also, of course, use such shipyards to refit stations if you like (again subject to the same rules as regular ships).
But no, in the absence of an appropriate yard, a station cannot be refitted.
Another minor drawback of building space stations with surface facilities is that you can't use any component stockpiles to speed up production.