Did the RG550 always come with a Wizard II?
Skunk stripes were first used on Fenders that had one-piece maple necks - that is, necks made from a single piece of wood - no separate fingerboard. *There was no other way to get the truss rod in there, so they routed a channel in the back to install it, and then put a (walnut?) strip in to cover it. *Necks with rosewood fingerboards didn't have them, because the truss rod could be placed into the neck before the fingerboard was attached. *Some players liked the look of the skunk stripe, so they strated putting them on rosewood-board necks too.
Since Ibanez makes their maple board necks with a separate fingerboard and neck back, they install the truss rod before attaching the fingerboard. *The bubinga stripe in no way makes this easier or cheaper. *I would guess that having to do the work of adding the bubinga, if anything, costs more. *But my guess is that the cost is offset in the end by a lower percentage of defective necks.
Personally, I'll take a modern, bubinga-striped, AANJ RG over an old one any day.