The chrome valve covers were a standard item on a '70 SS. The air cleaner, however was available in three different forms. On your build sheet, in the box for the air cleaner, there is a code. If you don't have cowl induction, option ZL2, then most likely you have a code "SS" for the open element air cleaner. The open element air cleaner had a chrome lid and a black base. If you HAVE cowl induction, then your code would be "DG" and the lid for that air cleaner is black. There was a third air cleaner, a dual snorkel closed version, that is very rare, and I am not sure the 396 cars even used it.
So, to recap my ramblings...
Valve covers-Yes, chrome
Air cleaner lid- code SS, yes; code DG, no.