I've been collecting the Amber pattern now for about 8 months and didn't know how to tell  the difference between the originals and the reproductions, until just recently.  The amber pieces are easier to distinguish..as the reproductions have a '76 embossed on the piece.  The location depends on the piece, but the plates have it on the outer rim on one side, the bowls have it just under the rim on one side, and the cups/sugar/creamer have it just below the lower part of the pattern on one side of the item.  It is located on the lower left side of the pattern.  The one thing about the amber recollection pieces is that the '76 is easy to spot.  Now, if there is something different to distinguish the other pieces that I don't know about I'd be happy if someone would please inform me.  Thanks!