Don't think Rotella has zinc any more. Its a moot point in an A as zinc was not an additive when the Model A was new. Zinc was introduced for the high compression engines of the 50's and 60's
I rescued a left and right inner sheet metal panel set that is marked as 30-31 sedan delivery. I am assuming these are for a Deluxe Delivery (130A or B) but possibly for a 79A.
Is the part in the attached picture for either of these A's?