Sight tools are great if you want to pay a lot for a good tool. What I've always done is use a brass punch and a hammer. The rear sight is fits tightly in the dovetail but it can be moved with with a hammer and punch. If you take your time you can adjust the sight without marking or damaging the sight.
USAF Retired, CATM, SC CWP, NH NR CWP, NRA Benefactor
To preserve liberty, it is essential that the whole body of people always possess arms, and be taught alike, especially when young, how to use them... -- Richard Henry Lee, 1787