An ATP holder with 1000 hours on multi-crew aircraft can just breeze in and take the exams - if you have 500 on the type used for the skill test, you don't have to go through a TRTO course, either. There's an exemption tick box on the application form.
You would be unwise to go for the exams without any kind of study, but PM me if you have any questions!
cheers
Phil