If you do lift the column, check if there are any shims between it and the base. AND note their position.
And when everything is back together tram it A change in torque applied to the individual fastenings can affect the alignment, even if they are metal to metal.
While its apart, can you find a more accessible location for the oiler, and then blank off the one that is causing the grief?
In fact, is it feasible to fit the new oiler in another location, and plug the original point, without moving the column at all?
Howard