Odd Radiator Leak Problem

Hello. I recently "finished" repairing my 1990 olds 88 after 3 months of intermittent work.

I ran off a curve on a rainy day and hit 4 fenceposts...I couldn't afford a new car and insurance wouldn't pay for the damages since the wreck was my fault so I bought a wrecked 1985 olds 98 bougham for parts.

Basically, I had to cut the front radiator assembly in half, cut the tack welds out on both cars and swap parts.

Anyway, when i replaced the radiator, there was apparently an extra plug on it for some sensor i dont have on my car...but the plug leaked. When i tried to pull the plug the pressure of the radiator fluid coming out shot the plug to who-knows-where. Could i just fill in the hole with JB weld or would i have to find the plug and reseal the hole with that?

Any suggestions are appreciated!