I just looked at my old style RV-7 rudder that I have in the shop (with the folded trailing edge) and it doesn't have those extra holes. My drawings for the new style rudder don't have those holes, either. I'll be at the airport later today and can see if my actual rudder has those holes or not--unless someone else chimes in. That's a high stress area, so I'd be reluctant to just guess.
I noticed the same thing a few years ago when I was building my rudder and called Vans about it. The response was that part is also used on the RV14 rudder and that what this holes are for. They told me that on the 7 I could either match drill the spar and install rivets or I could ignore them.
I chose to ignore them, but a couple of years later, it turned out be the perfect spot to rivet on a wire tie mount for the wire going to tail strobe...