Basically, yes. Multiple bg support hits a wall at IE8. Which is , incidentally no longer supported by M$ anyway ( since they aren't supporting XP). So I think it's safe to consider using multiple bg.. UNLESS you are hellbent in supporting older browsers ( always consider your audience, despite 'official' support) .
Incidentally, if you only need an extra image or two you could also consider using AP'ed pseudo elements and z-index.