[Who sells one that is 100% chromed? ]
I don't know who, but even if you find one that looks good on picture and affordable, not sure you would really get the expected.
The chrome process works best on convex shapes. The original pump volume is concave, meaning lots of cavities will have
less chrome applied because of the electro plating principle, where the chromium particules are attracted to the nearest surface.
Ideally you would need bath the pump a few times with the electrodes moved till these cavities are well covered, which would make the pump more expensive.
The other prob is that the pump casing is casted and its hard or near impossible to polish certain area's. So even if a thin layer
is applied, the surface being rough, it will not have a smooth mirror look. You will also get less protection in these areas.
If you want shinny look, I think you should get better results with a polished aluminum one.. Also much more durable (on finish).