convert from twist drain to garboard drain

Hey guys. I have an older 12' grumman boat that has the twist or locking type drain plug. The drain hole has about a 1/4" lip on both the inside and out side. I was wondering If anyone can tell me if I can buy a kit i can buy to convert the existing drain into a a Garboard drain. I was hoping that someone would sell something to fit in that drain so I didn't have to drill holes into my boat.Why I wanted to change it is because I wanted to mount an underwater led green light that has 1/2 inch threads. the light is made to screw in place of the threaded plug. If I can't change it Mabye I can just install a garboard drain somewhere else on the back. This boat has thin aluminum What would be the best garboard drain for this if i cant modify the existing hole.Here are pictures of my boat and the light.

is this it ? I never knew it had a name other than a brass drain.
It takes the 1/2" pipe thread plug.
I got mine from BPS for about $7.
They are also on ebay.