Use the complex profile to describe a railing module. Use it in a wall, but perpendicular to the railing direction - this gets the depth of the ironwork.
Multiply the modules along.
The other way is when you have complex smithing - hammered leaves and whatnot. Use a masked picture to knockout the background for transparency in the rendering.
I doubt if there's a pre-made object this detailed.
It is easy to model this with the complex profile method if you have the orthographic drawing, however, there will be many polygons. How much do you need to make?