Ah yes, I see what you're seeing about a lower poly object for the physics model. Makes a lot of sense. Those are the kind of things I can keep in mind for the future.
I managed to get my object (mr snowman) into the game and my files seem to work fine. I did notice however that ingame somehow the twigs have also gotten collision. Did I mistakenly not apply my own physics model and is it using one by SL itself?