Originally Posted by More_Miles
Once more confirmed I'm an id10t. Just checked and no, there isn't a corresponding inner hole for either the front or back extra hole...
Still begs the question, what are the extra holes for?
Sometimes extra holes have no end use. They are used in the factory for fastening parts to fixtures, in this case maybe a welding/line boring fixture or a jig to fit the subframe to the rest of the bike. You wouldn't use the shock mount holes in the latter case because then the shocks couldn't be fitted.
Or perhaps they are for some optional gear.
In any event, they cost money to make. No way they have no function.