It does have a couple of small holes in the top of the receiver, just like my lever action, so it IS drilled and tapped, but it also has those long slits.
I can't find any great pics online showing the slits very well but this gives you an idea.
http://www.bing.com/images/search?q=...lectedIndex=17
So it's dovetail rings that I need. Thanks NoSecondBest.