You might want to make sure the info you got wasn't for a totally unrelated model, by verifying that ordinary signals for the device are nec1 device 4.

You could test some nec1 device 4 signals for some other plasma TV and see if they work, or if you have learned signals in Pronto Hex, you could decode them and see if they are nec1 device 4.

I think LG uses more than one set of codes for Plasma TV's.