Has it been established exactly which model of Abu 507 you've got? The current MK2 is supposed to come with three shallow spools and one deep. Even if you've got an old MK2 (Goldmax), I seem to remember mine having a shallow spool. As an aside, there were two versions of the 507 Mk2 Goldmax. One version had no drag, backwind only. The other had a drag but also had an anti-reverse switch. As far as I'm aware the spools from the different models are not interchangeable. If you've not checked which reel you've actually got, you run the risk of the spool you've ordered not fitting.