The zinc (and other types) plater I used, added phosphating to his line but it was not profitable, so he directed the "hobby" guys to me. I've done items for Chevy, Mercedes, Mopar and Datsun owners.
In addition to the hood hinges (the springs should be darker to look heat treated); hood latch; hood auxiliary catch bar; all fender, hood hinge, hood latch bolts; all "J" and "U" nuts (well, almost all); strut rods (lightly); there's more.
I use stainless everything when phosphating, tanks, tools. My prime tank is a restaurant type, 12 3/4 X 11 1/2 X 3 7/8, and I still need to "splash" the bath over the spring hook. I use an 18 in long SST fish poacher for strut rods and other long items, a minute for one end, then with a pair of SST hooks, flip to the other end. A SST strainer gets small stuff out. A galvanized tub with cool water is used to rinse. Air dry, then oil.
Jim