The old tickets would only be good at PI and DQ if they were good there in the first place. For example, I have an old ticket I won as part of the 15th birthday celebration that is good for Epcot and MK. I'm keeping it as a souvenir, but if I wanted to use it, I could use it at Epcot or MK, but not MGM and AK. The newer tickets have a disclaimer that they aren't good at any park opening after May 1, 1998, so if another park opens in a few years, you wouldn't be able to use it there. So if your original ticket included admission to PI, you can go to PI. If it included DQ (which is less likely) you can go to DQ. When you have them checked at Guest Relations, they can tell you specifically how many days admission are left and which parks you can visit.