I do not think Stevens would have used Winchester sights. They had a number of their own available, the one on my gun is the No. 112 according to pictures in the 'Old Gunsights' book and the catalog pages referred to are from 1910 which would have been at the start of 425 production. This sight was also used on other rifles such as the Ideal. The front sight I cannot find pictured but appears to be the same as on the Cody Museum example and I am quite sure is the same as on my friends 425.
I got my 425 from a long time dealer and Stevens collector who was selling four he had acquired over the years - the other three he had were not in very good condition. When I got mine he said, "It has the best condition metal of the seven or eight I have ever seen" which indicates the rarity of them. He's been a dealer for many years and also runs a series of small gunshows. Mine has good metal but has some issues with the wood, which is still the original.
Of the ones I have seen I think at least three-fourths have repairs to the stock at the wrist (including mine). My dealer friend even had some replacement stocks made up for them years ago - the last I knew he still had them if any one needs one.
Headspace seems to be another problem they can develop (two of the four being sold when I got mine had problems). They lock-up similar to a 99 on the rear of the breechblock but unlike the 99 that has the front of the lever slide between the frame and the breechblock to securely hold it locked the 425 just pushes it up and has nothing solid holding it there. There also is a small spring on top of the breech-block that puts downward pressure on it that would cause the rear of the block to drop slightly with wear on any of the parts. I have never taken mine apart but looking at the patent drawings it appears the top rear of the block is angled and I assume there has to be a slight angle to the locking surfaces (like on a 99) to allow the rear of the block to swing down. This would mean that any lowering of the rear would increase headspace. Also there may not be as large of locking surface on the rear of the block as it would first appear because of the angled area.
It is one of my favorites and also is among those I looked the longest for. I have not shot mine yet but have ammo and plan to.
