I found a laser pistol. Then bought the sights. I don't see anyway to attach sights to pistol? Any suggestions?

select the item in your weapons menu any press X to mod it

dunno what it is on console but it should show what button it is at the top right

The laser pistol has a sight? Thought it was only the laser rifle.

The GRA Laser Pistol has an Iron Sights mod.

I wish i had the GRA when I did my energy weapons playthrough.

Thanks for comments. I have a laser pistol, but it is not the GRA Laser Pistol. I did the press x but nothing happened. So, wrong pistol probably explains it.

Yes, GRA mods will only fit GRA weapons. If the mod doesn't say GRA, then you can use it to mod regular weapons.