The "Red" Submariner is an example of a rare watch that has been duplicated by the replica makers.  Commonly they will use a standard modern-day replica Submariner case and simply add an "aged" (yellowed) dial and call it a day.  The example below is indicative of the common vintage fake Rolex Submariner.

Unfortunately there are some VERY convincing replicas on the market, that use the correct case, bezel, and even use OEM acrylic crystals.  As with any expensive purchase, "buy the seller" when deciding to pick up a rare watch.

ROLEX "Red" Submariner (Vintage)

Compare to Genuine Rolex Red Submariners on eBay

GREEN PRICE TAG & RED SEAL for ROLEX DAYTONA submariner US $42.99 Auction Ends: End Date: Friday Sep-10-2010 6:53:22 PDT Add to watch list

Rolex Dial Red SUBMARINER ref 1680 US $220.00 Auction Ends: End Date: Saturday Sep-11-2010 7:31:12 PDT Add to watch list

Rolex vintage Bible Book submariner red daytona 6263 US $46.99 Auction Ends: End Date: Saturday Sep-11-2010 21:00:11 PDT Add to watch list

Bezel Insert for Rolex Mens Submariner Blue & Red US $8.00 (0 Bid) Auction Ends: End Date: Sunday Sep-12-2010 12:44:37 PDT Add to watch list