If you are reading that you have to have the 1500 hours to take the ATP written test you are reading a 20 year old regulations book. That changed in 1997. That being said, there are no "frozen" ATPs in FAA land, maybe because of that history of not being able to take the written before you were ready for the checkride. Pilots would list on their resume that they had a commercial certificate and had passed the ATP (and many times the FE turbojet) written. The normal path for FAA certificates is to get your private then an IR then your commercial and ME and then your ATP. If you're doing a type rating the ATP and type rating checkride will be the same checkride.
Zond -
The FAA changed the valid time for the ATP written after you go through the CTP. It's 60 months - 61.39(1)(ii).