Mike, I hope I am not confusing things here.
Without adding a scope mount, there will be no issue. We know FlysAlot is happy with his.
That bottom link from my post is the Williams sight that came on the > Davidson's Takedown model 11125 <. As I said, there were some reports that adding a standard scope mount on that model at least partially blocked the view of the rear sight.
However, other versions of the Williams sight I have seen DON'T have the "serrations" you can see on the center of the mount, and they may be slightly different. Here is a shot of one like that, and it is the one FlysAlot linked to.
---> What I DON"T know is if the one from Williams that FlysAlot linked to (which DOESN'T have the serrations) is any different in height, or if having the usual Ruger or Weaver TO-9 scope mount on will partially obscure the view.
Hopefully he can jump in on that one.
Here is a view of another Distributor Exclusive. It is the Williams Model 1159 and it DOES come with the version of the Williams firesights that looks like the one Flys linked to:
That one has a 20" barrel vs your 18.5", and one difference I know for a fact is that the rear dovetail is roughly 3/4" further forward on a 20" barrel than the dovetail position is on yours.
Hope some of this helps.