The 322 will have the holes to bolt the plates in. But won't have the plates that I am aware of unless someone else added. Both of my 1st year (87) 332's had the holes and now have the plates. My fathers first year 430 (84) didn't have the holes-which takes some more time to install the plates.
There is also the tie rods, wheel bearings, axle bushings, steering cylinder ends and the center pivot that should be looked at for how much play they all have. It all adds up. I had to add shaft collars onto the center pivot to the outside welded on with a longer bolt as the frame was rounded out too much as well.
The issue with just extending the bolts you talk about is they were an un-even groove in so it will either bind the axle if you get them tight on level ground our it will have too much play on level ground.