I think it works the same. Kind of :/
I've installed it from the disc, and I now have Rockstar Games > GTA IV and EFLC
The GTA IV and EFLC folder are almost identical, except the EFLC has two more folders, TLaD, and TBoGT. I'm assuming those folders contain episode specific information. For example, the original GTA IV cars can be found in the EFLC folder, but then the bikes will be contained in the TLaD folder, and something in the .exe or one of the scripts will prompt the game to look in those folders for their episode exclusive content.
So far, I've managed to put the scripthook.dll and dsound.dll in the EFLC folder, and I'm assuming any mod in there will work for both episodes. It might work for only one episode if you put it in the appropriate subfolder, but im not sure. I'll try soon :/