well, you probably will end up replacing the barrel and stock. The improvement in accuracy is well worth the up grade. Where was the rust on the SS model? if it was on the barrel I wouldn't worry it. the trigger group, I wouldn't worry it, y, cause you might find your self really considering up grading to the volqaurtsen trigger group. You thought there where alot of things you can do to a AR, There are almost as many things you can do to a 10/22.
And when you a fully addicted to the 10/22, you might find yourself seriously considering selling your preban Oly so you will have enough (just enough) money to build that custom 10/22 with a Volqaurtsen stainless steel Receiver, match bolt assembly and trigger group, shilen match barrel and Bell and Carlson stock. And that is without the cost of putting a leupold scope on it.....