K.M.
We bought a gate mount kit when we put our gates up because we did not want to drill into the wood railings we have. All they are is a piece of wood that attaches to your railing and the gate would then attach to that wood. I found the kind that we have online and it says it can be used on wrought iron as well as wood banisters. Here is the info:
www.kidco.com search for item: Safety Gate Installation Kit Model K10
It was really easy to install and it has been up for almost two years now in my home and it is VERY STURDY. I have not had one problem with it.
Good luck!