Hmmmmm, one way glass wouldn't be practical on a roof (who would look in?) and it's usually illegal on the side windows of a car because of police reasons. I think you might be mistaking tinted glass for one way glass?
BMW offered cars with both sun roofs and moon roofs depending on what the user wanted, so they were definitely different items. Here's a post from a BMW list where they're discussing the differences:
"A Moonroof is glass. Usually a sunroof is
steel and painted the color of the car. You can open it, but you cannot see through it.
A moonroof on the other hand , is glass and usually includes a sliding shade to block out the sun ( and it's heat), hence the term moonroof. "
So the sunroof is solid metal and the moonroof is glass. Here's another reference:
http://www.sunroofs.com/faq.htm "Sunroof is the generic term used to describe an operable panel in a vehicle roof which can let in light and/or air. Moonroof is a term created by Ford in the 70's, yet is now used generically to describe glass panel inbuilt electric sunroofs. "
So again sunroofs were solid panels that you could open to let in air, and then moonroofs were the glass version.
I agree though that since then both terms have sort of become interchangeable and you can see both applying to glass versions. Some people use moon roof for non-opening glass ceiling windows and sun roof for opening glass ceiling windows ...