When I did my OE Cert 71 GTX, I talked this over with Roger Gibson. The original air cleaner on that car was smooth and most people told me that it was incorrect.

When we went through Roger's extensive collection of photos, we came to the conclusion that the Plymouths were more likely to have the smooth finish and the Dodge's were more likely to have the wrinkle finish. I don't remember what the Chryslers had.

But there were exceptions both ways.