What are the differences between Loom IBM and MAC box contents? I have two sealed ones and the MAC version weights 358 g even with the Hintbook enclosed sticker! IBM 1.st release weights 432 g. Museum doesn`t give a clue where the weight difference is coming from. There are obviously disc differences (3,5" vs 5,25") between the boxes, but ibm is 74 grams heavier and my scale should be pretty accurate! Is it Adventurer magazine or something else?