One, it's not the best galvanise job in the world and two, as soon as any hole(s)get drilled through it- as they do-to accept the various nuts, bolts, frames etc., the whole concept of it being galvanised is undermined.
Just to re-assure you a bit, no the idea of galvanising isnt undermined. Galv isnt like paint intended to protect just by covering the surface. It also protects by electrolytic action when penetrated. Sure this means it will gradually erode away but if the chassis is hot dip ( which is what it looked like when I had a quick glance) then this will take a long time. That said, probably still better to waxoil it.
