I for one don't like being "dictated" to collect two of the same thing just because a guide will give a different identification number to each.

Look at it this way: If Groucho appears on one side of a broken mirror, and another Groucho pops up on the other side, are they the same or different Grouchos? Watch "Horsefeathers" to find out, paying close attention to when they actually walk through the mirror frame to exchange places.