Just re-read these interesting bits from back in January 2008, which indeed do not mention which of the keys is used, just the fact that you should own the Isis II before claiming the gold (did you?)
PUZZ wrote:I will be introducing a pyramid scale award system though for those that claim gold coin awards from real pyramids that own all the isis series to date. For example own Isis I only and claim a gold coin = £500 or own isis I and II and claim a gold coin = £750.00.
Or should we consider the Ramisis as not yet released? In that case you can hold on to the gold coin until the Isis V release and then claim 1000 pounds!
PUZZ wrote:The current gold coin if claimed for Isis I is worth £500, but if you happen to have a gold coin that you havent claimed the money for yet, and you keep it til isis V lauch we will double the value to £1000 but this rule only applies upto the date release of isis II
Another interesting bit form the same thread tells about keys and (real) pyramids:
(Some of the Hamleys Club already have a Ramisis key, can they confirm if it's different?)
PUZZ wrote: The same pyramids will be used for all isis 1- IV , all the keys are different for each puzzle, but the pyramids have been fitted with master locks, which allows all the keys to fit. So if you dont buy isis I, but buy isis II and solve it, you can still go for a gold coin and open the pyramid with the isis II key.
You must own the isis in the correct order, and register them on our database in the correct order to claim the additonal £250.00
I started this thread when a gold coin winner from the UK was added to the winners list, but did not post his story on the forum. We still do not know who he is, where he lives, nor which piramid he took his gold from, that's what I meant by "another UK pyramid was robbed".
PS: I know the quotes are from within the 5% forum, but I believe these are no secrets, and may even encourage new adventurers to buy the Isis I puzzle FIRST, and then the Ramisis.