Kevin, When the new machines came out IGT gave the Casino's new clear and colored strike cases that were the new style and it was up to the casino to change the old ones over. Some casino's like the Reno Hilton got carried away and were putting the old commons in their extra red cap cases. Caused a few problems there for the collectors until they figured it out. Also some private sellers were doing the same. It's trully "buyer beware" and a great asset to have the referance books handy.
Now IGT sends all the strikes colored and clear already in the new cases.
Dying the airtites is probably the hardest and worst job but it keeps all my cases the same size and easy to spot in the racks. The new way of using a sharpie seems to work well but to me isn't the same as seeing the whole strike in a colored case. Hope that helped a little, Jeff