I am well aware of what they looked like new, I have owned many NOS ones that were still in their original boxes that hadn't seen deterioration. I am also aware of the color variances because of how polluted the clear zinc was and how polluted the dichromate dip was. You can be sure the vendors for Chrysler used some pretty polluted chemicals. I have never used anyones "services" because I have always restored my own motors (before anyone had a service for it). I buy an NOS 70-73 C-body motor on Ebay because they are cheap with the incorrect part number, I've paid avg of $65. then buy an NOS switch plate, usually $25. Replate the cars original barrel for about $15 and reassemble with new Glyptal paint slopped on the wiring connectors. Total investment $100.
Attached is a pic of NOS wiper motor barrels on the left and replated ones on the right that I have done.
And yes the glossy clear coated engine bays are inacurate as well.