One of the difficulties in putting a price guide for Proclamation coins together is that there are a huge amount of varieties of some of the coins included. Although our price guides give a straightforward single price for the Brazilian Johanna; the 1787 Shilling and the Mohur (as examples), collectors of these coins in their nation of issue have identified numerous varieties of each of them.
The Proclamation coin that has the most number of varieties is the Spanish Colonial silver dollar - Peru alone produced some 8 billion silver dollars over a 300-year period! The fact that at least three other countries (Spain, Mexico and Bolivia) also produced eight reale coins throughout this period complicates matters further, so what we end up getting in our price guides is an earnest attempt to provide a general guide to what one might expect to pay for a common "type" coin. Both of the publishers go out of their way to advise budding collectors that these figures are a guide, however many collectors conveniently overlook these clarifying statements and just go on the figures published.
A forthcoming Heritage auction includes a coin that will really pose such collectors earth-shattering problems: a Colombian 1770 Nuevo Reino Pillar Dollar. The 1770 Nuevo Reino Pillar Dollar was unknown to exist until about 3 years ago when exactly fourteen coins where found in the old foundations of the Nuestra Senora del Pilar church in Bogota. Each of the 14 coins found were sold to private collectors and museums in Colombia and Spain, the original purchaser of the coins kept the two highest quality coins for himself - the piece in the Heritage auction is one of them.
With a pre-sale esitmate of US$60,000 - US$80,000, it's unlikely that this particular Pillar Dollar will appeal to Australian Proclamation coin collectors, but this auction does show that proclamation and colonial coin collectors are part of a much broader world-wide market for quality numismatic items. One of the benefits of including a set or even modest range of proclamation coins in an Australian collection is having an asset whose value is largely determined by activity outside Australia - great when economic activity here is low.