I had a set of stock KX250A5 rear shocks rebuilt by Radd Suspension in Qld, I'm in Vic, within 1 week, they had straightened the shafts, re-chromed the shafts, new seals and re-oiled & re-gassed without spoiling the stock look by fitting a valve on the reservoir AND repainted them! Plus I wanted the damping relieved a touch which they did.
They look and work as new, 1 week turn-around and I think it only cost me about $290 For sure they wouldn't work as good as a properly set-up modern shock but they sure as hell work better that a modern shock that isn't set-up right.