Didn't work. Another suggestions. Next stop, gunsmith!
Unfortunately, there's not a front sight pusher for the Rami available, that I know of.
What you might do, in addition to the oil soak, is use a heat gun to heat up the slide, which should expand / break loose the dove tail around the sight and allow the sight to move, knocking it (from right to left, as memory serves) with a brass or plastic punch.