I had a Pre-64 Model 70 in 220 Swift. Like yours, it was a good shooter. I used it a lot in South Texas for coyotes and such. Finally though, I decided that it was more valuable than I needed, so I decided to take the equity out of it and buy another 220. Finally found a Ruger 77V and sold the Winchester. Never been sorry for doing that.
It's been a number of years, but I think that the barrel on mine (and yours) is a blackened stainless that Winchester put on the 220 and the 264 back then.