https://www.ibanez.com/eu/products/model/sr/
New Models? Ibby now list a new SR600, Old ones of which there were a couple of variants, mainly without Mid Freq Switch, 2 position Switch (like my 2010) then 3 Position Switch. like this https://www.ibanez.com/eu/products/detail/sr600_07.html : Ibanez do some lovely flamboyant finishes, and some lovely wood on the more expensive models - but i just love the plain natural... was the only finish available on these variants.
The 400 has a different neck, and Powerspan pickups and is basically a pretty SR300 - (QM Quilted Mapel top...)
The 500 and 600 has the longer tang neck made from different woods and different bridge.
The 500 gets Okoume body n plainish finish, with Bartolini pups
The 600 gets Ash in a fancier finish and swaps the Barts for Nords...
Neck profiles are all the same Ibby Skinny...