The 83 model was the first year to incorporate the rudder adjusting features that you mentioned. They're very nice and work well. The new type upper castings are all you really need to adjust rudder rake. You might try giving Dan Berger email. He's in your Virginia Beach area and sometimes has a lot of used parts. Search this forum for his name, and you'll come up with his email address eventually.

You might take a look at an old 'On the Wire' article that describes the drilling process, if you have to go that way.
http://www.thebeachcats.com/OnTheWire/www.catsail.com/archives/v2-i7/feature3.htm

As the article suggests, I would very much recommend a drill press if have access to one. If the drill bit 'wanders' or grabs, then you may create a bigger problem than you have now.

Good Luck.