Is the blade wood? IF so I would say yes. I would drill it big enough to finish the hole with epoxy and paint. If it is fiberglass I would try to find another way.
On SBD.com the rudder looks like a cassette which doesn't pivot. Maybe it's meant to be unshipped in shallow water?
If it pivots you may need a provision to hold it down while sailing.
Yes, you can drill a hole in the trailing edge. However, you won't be able to just pull on the line to get it started. I have to push the headstock in to get it started, and then I can use the uphaul line. I wrap it over the top of the headstock and along the tiller to a clam cleat. I keep mine up in the slip, because when it's down, wave action works the pintles and gudgeons, and I don't want it weemying out the gudgeons, forcing a replacement.
Note also that I have added a substantial teak block for the headstock in an attempt to stiffen up the works, as the cheap-@$$ riveted spacer tubes loosen up over the years and create play in the headstock.
Like Brian, I have installed an uphaul on my O'Day 222, which shares either the same or very similar rudder assembly. The previous owner kept the rudder down on his slip, and it did wear deep grooves in the pintles as well as the pivot bolt hole in the side plates . I've had the pintle grooves welded in, filed round and now keep the rudder in the up position when not in use. I also agree with Brian on the flimsy headstock and I also used wood between 1/4" aluminum plates rather than the 1/8" original side plates. I did reuse the spacers held in place with stainless bolts. Mine is hooked up similar to Brian's, but mine almost always comes up with just a firm pull to get it started. The hole for the uphaul is 14" below the pivot bolt. Sorry for the less than pretty second photo, but Gust-Oh is tucked away for hibernation until spring.