Setting up an old lamp-post & lamp-top with an electric light?

[d000hg]

A place near me has a few old iron lamp-posts, which is something we are after for our garden. It's not something I know much about, but it appears the lamp-heads are sort of interchangeable so we can source them separately - is this something that is easy to do or bodge?

In terms of getting electricity in, I am hoping the posts are hollow so it's a case of feeding a wire up and through into the head and somehow fitting a modern bulb-holder inside?

e.g like buying this and this:

 

[JohnD]

yes, the posts are hollow. they originally had a gas-pipe going up then, later converted to electric. Many have an access hatch near the base.