The front sight you describe is stake-on. It can't be reused, all you have to do is pull it off with a pair of pliers, with care that you don't slip and scratch the slide with the pliers.
I did mine with a LWD multi-tool that's made of brass and has a front sight hex nut wrench, and a vise with hammer and delrin punch. The sights I installed were Glock factory steel sights, not night sights. I wouldn't tap a rear sight with tritium vials, it may rupture the vials.
The LWD tool had some flashing in the walls of the wrench, all I had to do was run a razor through the walls of the wrench to remove the flashing. To install the new front sight, I degreased the front sight and screw with rubbing alcohol and thoroughly air-dried both. I then put the front sight in the slide, put the screw in the wrench with the threads straight up toward the ceiling, and used a q-tip to apply a small amount of blue loctite to the threads of the screw. Then I looked through the muzzle hole in the slide to position the screw correctly in the front sight, and I tightened the screw down most of the way until the sight only had a little play in it. I moved the sight to be as best aligned as possible, then held it down firmly against the slide with my thumb while I tightened the screw down with only the amount of strength from my thumb and forefinger turning the front sight tool. I then checked that the sight was aligned correctly by eye. I let the loctite set for 24 hours before applying any oil anywhere near the sight, and I let it set for 48 hours before shooting with it.
The vise part is tricky. If you do it wrong, you could destroy the slide. You have to pad the gripping surfaces of the slide obviously. Also you don't want to apply pressure to the slide rails, the ejection port, or any portion forward of the ejection port. You can use little strips of wood covered in masking tape, I used layered cereal-box cardboard taped to the vice. I used a DPMS AR-15 Delrin punch(it's plastic) and a hammer to tap the old rear sight out, I tapped the sight out toward the right side of the slide. Then I put a drop of oil on the bottom of the new sight and another drop in the slide dovetail, and tapped the new sight in from the right side of the slide. The tricky part is getting the sight centered just right so there's an even amount of extra space on either side of it, that probably took me 20 minutes.
Here are two pictures showing where to grip the slide in the vice, you'll likely need to use small pieces of wood so that the slide will sit high enough in the vice without putting pressure on the slide rails: