It is certainly no JS100/1000; both of them had the
coil split.
But your description sounds like a white Radius to me, which evolved into the JS line in '91. Those are awesome. Pics please!
http://www.ibanezregister.com/images...440r-ld-90.jpg
Which pickup layout do you have? HH, HSH or HSS?? Is there just the IBZ-Print on your pickups, or something like "IBZ V2" or "IBZ/USA"? This will help us designate whether it's a R540 or R440.
PS. Yeah, splitting the pickups shouldn't be a problem. The only thing you'll need is a DPDT push/pull switch and some inspiration from the JS100 wiring.