Eric, I spoke to a couple of people, both are also aware of it's relatively recent appearance in official documents, but neither knows any more than you do. One theory offered however, was that a while back there was a surge of new documents, with the improved photos, etc. Among these new documents were several items that never got beyond testing, but documents were prepared anyway by/though Picatinny. Their theory is that this was the case with the Hawk; a prototype that was later dropped.
As far as the grenade's construction, the photo was clearly photoshopped to remove the background, this is commonly done for technical publications. When doing this, if the background is particularly cluttered or of a similar color however, one has to be very careful while photoshopping or they remove parts of the ordnance item along with the background. This is most common if the munition is handled and photographed by one person and photoshopped by someone back in an office. I would guess that this may be part of the explanation for some of the curious construction appearance, as we both know that this photo is not a "joke".
Not the answers that anyone wants, but the best I've been able to get so far. I'll let you know if I hear anything more.
