Daniel,
Four years later, but better late than never, at the risk of being accused of creating a zombie thread. AFAIK, they're all translucent. I've seen quite a few. Some photos of them may appear to be opaque depending on lighting and background underneath or behind them. For those - as seen in eBay auctions - that have a number of photos showing the cover, it's apparent from at least one of them that it's translucent.
John