Like to replace the black rear sight blade on 27-2 with a white outline blade (that I have). Do I need a special tool(s) of sorts? G/smith nec. or do-able at home? Any advice appreciated. Thanks..GR

Yes you do need a special tool, I have never replaced one but Midway USA has the tool. Part # 630-412 $23.99, 1-800-243-3220.

I replaced one on a 27-2 and did not buy the special tool, although it may have made the job easier. I think the FAQ section of the forum here has the proceedure outlined, and If I recall, the part kit from Midway had instructions included. The tricky part was the reassembly and preventing the launch of the two parts called (I think) the spring and plunger. These are easily sent into space, and the plunger you'll see is even rocket shaped for increased ballistic characteristics. Its generally recommended that you do the reassembly inside a plastic bag to catch them when they fly loose. That didn't work too good for me and at my wife's suggestion, I managed to do it under a sheet of the thin plastic that you get from the dry cleaners. Its thinner and more transparent and i think that helped.
Good luck.

I recall Brownell's last I looked had a rear sight kit with the special tool, and two different sized screwdrivers. The special tool ensures the concrete soluble springs don't go winging off to a different time space continuum.

the special staking tool makes rebuilding the rear sight easier, but its not absolutely necessary. a dulled nail will suffice for a homemade staking tool...
you'll need more than just the rear sight blade though: you'll also need a new sight screw and corresponding nut. these are rendered unusable in taking off the old rr sight blade.

Do read the FAQs on this first. You will otherwise likely loose your plunger and spring.

I believe S&W sells "sight rebuild kits" for like $11 with a blade, windage nut and screw, maybe the plunger/spring, too. Look on their web site, I know I saw it there a while back.

Because the nut/screw are staked, you break them when removing them. It is (sometimes, in a pinch) possible to drill the end of the screw and salvage the nut, but you still trash the specialized screw.

I was afraid of that; however; thanks, gents.To the g/smith manana.........gr