They do. Spirits are 10% chance from their respective bags. Darkmoon Eye is a 2% drop from the darkmoon bag. So, across a large sample size, it should take an average of 5 months if you hit the faire daily every time it's available. Of course, there's going to be a lot of variation with that low drop rate, so there's going to be people who don't get it even after a year of trying -- and people who get 2 on the first week. Right now Eyes are quite rare on the AH and fetch ~30k, but at that 5 month mark, supply should start outpacing demand. I think this is the 3rd DMF since 5.1, so if you can wait another 3 months, then a lot of people will have surplus Eyes, and prices should start trending drastically downwards.