as others said, a vintage p90 is what was in the guitar but was boosted by a rangemaster treble booster into a laney amp. if you have a similar rig, get the duncan vintage p90 bridge model. its a bit hotter than a 60's gibson p90, but most people like that in the bridge position, especially of an sg.
now if your rig isnt similar, then knowing what youre playing though will help us point you in the right direction