Update legacy Donahoe to Icon specs?

Have some 2005 era Donahoe's considering updating @ Icon.

Anybody do this?

 

I don't know exactly what they update but the seal head changed a little, different wiper, and they have a solid piston now. IMO just rebuild them and run them. The "updates" won't change how it performs. I can do it if you want to ship them or if your in SoCal there are many options to rebuild without the extra $$$$ to update them.

 

Any suggestions for removing external corrosion, and what sort of clear coat would work?