[Lava]

The save will most likely not work, as in the Infinity Engine some stuff is stored in savegames (like character names, areas you already visited, worldmap, soundset lines...) and some are not (like items, item descriptions, etc.) It doesn't matter that you haven't reached BG2 portion of the Trilogy; there is already a lot of modded data stored in your savegames. You will probably encounter a lot of bugs, like wrong names, worldmap problems, messed up biographies etc. And there is a chance of much worse problems than those I mentioned.