73 Duster Manual WW Pump

I have my manual washer pump out of the car and am thinking of sandblasting the metal base. My question is: is there an easy (non destructive) way of getting the rubber pump itself out of the metal base? On the back of the base the plastic hose fixture is six-sided which makes me suspect it might be threaded in to the rubber part through the base.

Sorry don't have a picture.

Or is it better to just mask off the rubber and not disturb 42 year old connections?

Thanks