Both the new chassis (Plus 4 and 4/4) I got from Terry came powder coated but I sprayed them with two heavy coats of 2K Gloss Black for a little extra protection.
The 4/4 project I bought a couple of years ago, came with a new chassis which was supplied powder coated but subsequently got galvanised (not by Terry but by a third party firm), sadly, they failed to drill one of the box sections and its blown. Not affected the alignment of the chassis or to render it scrap but just looks unsightly!
Arwyn