Parker Hale PH-5B on my Eddystone P17

[oldfoneguy]

The bolt stop is the part you pull out to release the bolt from the receiver.
The bolt stop springs are slightly different on a P14 and a US Model 1917.
The P14 spring tapers at the rear and the Model 1917 spring is straight.
The PH sight replaces the round part that retains the spring on the receiver so it won't work
with the non-tapered Model 1917 spring. Parts that are simple to replace and available. - Bill

edit to add: No holes will be have to be drilled or permanent modifications made, the sight is designed for the rifle.
However in my experience the sight axis screw which is very fine and somewhat frail has a tendency to
be frozen on a 100 year old rifle. If replacing the bolt stop spring I would order an axis screw and nut just in case.