A proof coin of this era is generally an "official" issue struck from specially prepared dies by the Soho Mint, they were distributed for numerous reasons at the time (advertising, samples, gifts etc) the proof is a copper issue, so has been struck on a copper blank. Whereas restrikes, were coins that were struck "unofficially" from genuine dies at a later date. A die sinker Taylor bought some scrap from the Soho mint in the mid 1840's and included were a number of the original dies. These dies were then re-used to strike further examples. The restrike you have linked is Bronzed, and is therefore a "bronzed" copper restrike. Struck on a specially prepared blank that had been bronzed prior to striking. Peck contains a wealth of information on this subject, it is a fascinating read!!