Consider the mystery solved.
According to Reynold's Kitchen, the difference between the two sides of aluminum foil is just a result of manufacturing.
Why is only 1 side of aluminum foil shiny?
Is There a Difference Between Tin Foil and Aluminum Foil? – LifeSavvy
Why Aluminum Foil Has a Dull Side and a Shiny Side - Reynolds Aluminum Foil Wrap
The Difference Between Aluminum and Tin Foil
People are just realising what you should use each side of tin foil for
Which side of foil should we cook on? - Quora
Eric Akis: How to use and recycle aluminum foil - Victoria Times Colonist
What You Should Know About Aluminum Foil
Is there a right side on aluminum foil
My aluminum foil shows which side is the nonstick side. : r/mildlyinteresting
Can Aluminum Foil Go In The Oven?
Should You Use Aluminum Foil With The Shiny Side Up Or Down?