thanks dee, just looking on the bay and saw one that said hs and didnt know. this is only my second ibanez guitar, so i dont really know much about the different trems. i'm a rythem player and just wanted another guitar with a locking trem.
The only thing it might be is the sustain block, which is taller on the original (non-recessed) versions used on the RoadStar series. If you install a long-blobk version on say an RG550, the block will stick out the back just a little bit. Pretty sure the blocks are interchangeable and held on with 3 flat-headed phillips screws that hide under the bridge saddles.