I've acquired a 617-2 not long ago, s/n CBF31xx. It was plenty dirty when I got it, but it cleaned up pretty well. There are dark spots on the face of the alloy cylinder which I *think* I can get out, but I haven't really tried.
It shoots alright, not as well as my K22 or my model 41. I have only put 350 rounds through it, so we may accommodate to each other. But as is, it's a nice plinker and the ten round cylinder is a hoot with anyone who picks it up.
My K22 is much harder to keep clean. The cylinders clog up in that gun after only three firings. I bring a short brush whenever I shoot that gun, because you have to clean the cylinders every three (by six) rounds.
That's true for CCI SV and Fed. GMT.
The 617 on the other hand stays loosey goosey, no troubles.
The alloy does look weird. A stainless cylinder would look way better.
I'll shoot it till it pukes, then maybe think about a stainless cylinder. Meantime, other than looks, it's fine by me.