The painting process has been quite straight forward until relatively recently so its not something that really got covered indepth
Most folks still just go with primer then Satin black paint on everything right off the bat then maybe a little weathering and call it done but a number of folks in the community in recent years (myself included) have decided to dive a little deeper into it, adding various degrees of and types of texture, imperfections, brush strokes and other tells that the original props had.
It's a bit of a rabbit hole
The general rule of thumb though for painting alone as far as accuracy is concerned for the original packs is everything is primed with a grey spray primer.
The shell is painted satin black with no metallic weathering, then sanded or scratched in various places to show some of the primer.
The various components that bolt on to the shell and the thrower, if theyre made from aluminium are sprayed satin black then weathered back in places to show the metal.
Or if the components and thrower are resin, parts are either painted silver/chrome, then satin black and weathered back to show some silver paint or painted satin black after primer and weathered using a little silver/chrome paint on some of the edges, etc to simulate a similar look.