I would say if there is no raised casting, then you've got a set of the more recent covers produced by Ansen for CP beginning in the late 1990's or early 2000's.
Here is a set of Buffed Aluminum covers which have both the raised casting numbers and the Japan id, obviously NOT chromed. Credit to whoever originally posted this on the site about 5 years ago.
Here is a set of original Chromed covers bought out of the Motion Catalog. They are both Chromes AND not from Japan.
I am no expert. For all I know the buffed aluminum covers could have made up the majority of what Joel sold. My personal experience has been that the chromed ones with Motion badges are the only type of virgin valve covers I have seen. I say this both on ones I have seen in person ADN what I observed in pictures, catalogs and descriptions I have read.
All of the buffed aluminum covers I have seen have either had emblems removed, attached or "restored". I beleive the majority of covers I have seen recently sold started out as buffed aluminum ones, but somehow have become "super polished" and called restored. I cannot begin to speculate on what was on the under-side of these covers.