Afternoon

My new 989 looks to have a pinned in front sight but it also has the hole for sight retaining plunger of some sort.

Anything special about the 989 front site replacement?

You could check the owners manual if you have one available.

I believe the pin you see in the side of the ramp base secures the spring and plunger that hold the sight blade in place..... so that the spring and plunger don't come out when depressed and released. To change the blade, you depress the plunger and lift the sight out of the slot in the top of the ramp.

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Ret. LE, FA Instr, S&W Armorer

If you have a "Classic" style interchangeable blade there will be a hole (about 1/8" id) in the sight base just above the bore when you look "down the barrel" from the muzzle end. To remove, you push these sights towards the cylinder and lift the muzzle end. They have a cross pin but you DO NOT remove it.

Thanks guys-- I did finally figure it out as the front sight was kind of stuck so wouldn't move rearward easily. A few taps with a plastic mallet & it now moves rearward.