Here are my 128k logic board photos, which show top and bottom and many angles. Click on the individual photos, then click on the little "All Sizes" button above the photo to see the large size. This board came out of a stock Macintosh 128k that was built in 1984.

Henry, I would appreciate it if you could pick on the my photos and then mark it with the "decoder board" you are speaking of. Or otherwise mark the location. (Are you speaking of the 7 holes shown in my photos between RP1 and C34? Someone named "Henry" mentioned this in the commentary section at the bottom of this Folklore page.)