RE: the metal sides thing - I can confirm that some (not all, but especially older 80's era LD games) had a metal side that made the whole disc heavier. LDs are, after all, two sides glued together - from what I understand poor application and deterioration of the glue is one of the causes of "laser rot", though it shows up within a few years and makes the disc unplayable so I don't think it would be a worry at this point. Just wanted to mention it for no good reason.