I'm surprised someone mentioned a hammered finish. For 27 years we have always applied a brushed finish. For the first ten or so years it was a straight brushed finish, then for nearly ten years it was a wavy brushed finish I applied by hand. My hands are too arthritic to do that anymore, so this year I acquired a bench top drum sander to apply the straight grained finish like we had done many years ago but more consistent than our supplier had done. That straight grained finish is what I see on the side of the panel that you have on the bottom, i.e., that is the straight grain finished top. The red bottom side of the panel that is on the top in your photo was 99.9% likely not finished at all, just had the raw mill finish of the aluminum sheet the panels are laser cut from. On a very rare occasion I do sand that bottom side a bit too, to knock down some raised edges around the holes.
As PB mentioned, we dedicate a page in the manual (page 13) to showing the proper orientation of the top of the panel using the hole layout as a guide.