To Paint or not to paint

[Canuck]

I am in the process of restoring a 71 W30 convertible. I just recently acquired a NOS short block specific to the year and tagged as a warranty replacement block for this application.


My question is twofold:
When a dealer replaced an engine back in the day with a factory replacement unit,would they have painted the block or entire assembly or left it bare with just the painted original parts,assuming the paint had not been boiled off.

For my restoration I am considering leaving the block bare but with a clear protective coating that will preserve the inspection marks and not rust. The other parts would get a full detailing as the car is getting a body off frame roteserie restoration.

Thaought,comments input from anybody who worked in a dealer or had a engine replaced under warranty and has recollection on how it was delivered back to the customer.
Not including a ZLI what would have been the practice?