undersized isn't a problem for such an old film union.
Remember, its very, very old, prints from that age aren't particularly good. They are only mono sound so you can preserve quality @ a very low bitrate and the video will be crusty black and white which is extremely highly compressable
Even with AC3 its hard to get the movie to 700mb without saturating the codec (that's wasting bits).
Then again, experience says if there's no ripper tag/source tag, there's a high chance that there'll be encoding errors and what not with it.
Still being undersized means very little for that file
