I had a sea salvaged 8 Reales (or so I thought it was) that looked just like the one in the photo ..... Mine had a cracked up cheek and all the cracks ran the same direction.
These cracks (planchet flaws) can be found on all sorts of coins (including ancients) although most believe the causes are different. Normally they indicate a genuine coin. However, at this time, studies are being done by several collectors on the metal content of 8 Reals and Cap & Ray coins. Apparently, in the 19th and early 20th Century very deceptive fakes were being made for the China Trade. These fakes have been assimilated into the coin market LONG AGO (just as the Micro "O" Morgan Dollars). At this point in time, there are good arguments on both sides of the matter. Posters here can go to Coin Community and look up SwamperBob's posts in the Foreign section.